If you can not add something to the imports viewer you can write your own. Here is the simple example (it is slightly modified example referenced at this hexblog entry and located here with added double-click functionality, added columns, removed exports and fixed bug for a case of unknown origin of the imported function)

import idaapi
import idautils
from idaapi import PluginForm
from PySide import QtGui, QtCore

class ImpExpForm_t(PluginForm):

    def imports_names_cb(self, ea, name, ord):
        self.items.append((ea, '' if not name else name, ord))
        # True -> Continue enumeration
        return True
 

    def BuildImports(self):
        tree = {}
        nimps = idaapi.get_import_module_qty()

        for i in xrange(0, nimps):
            name = idaapi.get_import_module_name(i)
            if not name:
                name = "unknown"
            # Create a list for imported names
            self.items = []

            # Enum imported entries in this module
            idaapi.enum_import_names(i, self.imports_names_cb)

            if name not in tree:
                tree[name] = []
            tree[name].extend(self.items)

        return tree

    def PopulateTree(self):
        # Clear previous items
        self.tree.clear()

        # Build imports
        root = QtGui.QTreeWidgetItem(self.tree)
        root.setText(0, "Imports")

        for dll_name, imp_entries in self.BuildImports().items():
            imp_dll = QtGui.QTreeWidgetItem(root)
            imp_dll.setText(0, dll_name)

            for imp_ea, imp_name, imp_ord in imp_entries:
                item = QtGui.QTreeWidgetItem(imp_dll)
                item.setText(0, "%s" % imp_name)
                item.setText(1, "0x%08x" % imp_ea)
                
    def dblclick(self, item):
        try:
            idaapi.jumpto(int(item.text(1).encode("ascii", "ignore"), 16))
        except:
            print "Can not jump"

    def OnCreate(self, form):
        """
        Called when the plugin form is created
        """
 
        # Get parent widget
        self.parent = self.FormToPySideWidget(form)

        # Create tree control
        self.tree = QtGui.QTreeWidget()
        self.tree.setColumnCount(4)
        self.tree.setHeaderLabels(("Names","Address", "Ordinal", "Source"))
        self.tree.itemDoubleClicked.connect(self.dblclick)
        self.tree.setColumnWidth(0, 100)

        # Create layout
        layout = QtGui.QVBoxLayout()
        layout.addWidget(self.tree)

        self.PopulateTree()
        # Populate PluginForm
        self.parent.setLayout(layout)


    def OnClose(self, form):
        """
        Called when the plugin form is closed
        """
        global ImpExpForm
        del ImpExpForm
        print "Closed"


    def Show(self):
        """Creates the form is not created or focuses it if it was"""
        return PluginForm.Show(self,
                               "Imports / Exports viewer",
                               options = PluginForm.FORM_PERSIST)

# --------------------------------------------------------------------------
def main():
    global ImpExpForm

    try:
        ImpExpForm
    except:
        ImpExpForm = ImpExpForm_t()

    ImpExpForm.Show()

# --------------------------------------------------------------------------
main()

If you can not add something to the imports viewer you can write your own. Here is the simple example (it is slightly modified example referenced at this hexblog entry and located here with added double-click functionality, added columns, removed exports and fixed bug for a case of unknown origin of the imported function). See the function BuildImports for creating additional imports (manual_func1 and manual_func2)

import idaapi
import idautils
from idaapi import PluginForm
from PySide import QtGui, QtCore

class ImpExpForm_t(PluginForm):

    def imports_names_cb(self, ea, name, ord):
        self.items.append((ea, '' if not name else name, ord))
        # True -> Continue enumeration
        return True

    def BuildImports(self):
        tree = {}
        nimps = idaapi.get_import_module_qty()

        for i in xrange(0, nimps):
            name = idaapi.get_import_module_name(i)
            if not name:
                name = "unknown"
            # Create a list for imported names
            self.items = []

            # Enum imported entries in this module
            idaapi.enum_import_names(i, self.imports_names_cb)

            if name not in tree:
                tree[name] = []
            tree[name].extend(self.items)
        tree["manually_added"] = [(0x01, "manual_func1", 3), (0x02, "manual_func2",4)]
        
        return tree

    def PopulateTree(self):
        # Clear previous items
        self.tree.clear()

        # Build imports
        root = QtGui.QTreeWidgetItem(self.tree)
        root.setText(0, "Imports")

        for dll_name, imp_entries in self.BuildImports().items():
            imp_dll = QtGui.QTreeWidgetItem(root)
            imp_dll.setText(0, dll_name)

            for imp_ea, imp_name, imp_ord in imp_entries:
                item = QtGui.QTreeWidgetItem(imp_dll)
                item.setText(0, "%s" % imp_name)
                item.setText(1, "0x%08x" % imp_ea)
                item.setText(2, "0x%08x" % imp_ord)
                
    def dblclick(self, item):
        try:
            idaapi.jumpto(int(item.text(1).encode("ascii", "ignore"), 16))
        except:
            print "Can not jump"
        

    def OnCreate(self, form):
        """
        Called when the plugin form is created
        """
        # Get parent widget
        self.parent = self.FormToPySideWidget(form)

        # Create tree control
        self.tree = QtGui.QTreeWidget()
        self.tree.setColumnCount(4)
        self.tree.setHeaderLabels(("Names","Address", "Ordinal", "Source"))
        self.tree.itemDoubleClicked.connect(self.dblclick)
        self.tree.setColumnWidth(0, 100)

        # Create layout
        layout = QtGui.QVBoxLayout()
        layout.addWidget(self.tree)

        self.PopulateTree()
        # Populate PluginForm
        self.parent.setLayout(layout)


    def OnClose(self, form):
        """
        Called when the plugin form is closed
        """
        global ImpExpForm
        del ImpExpForm
        print "Closed"


    def Show(self):
        """Creates the form is not created or focuses it if it was"""
        return PluginForm.Show(self,
                               "Imports / Exports viewer",
                               options = PluginForm.FORM_PERSIST)

# --------------------------------------------------------------------------
def main():
    global ImpExpForm

    try:
        ImpExpForm
    except:
        ImpExpForm = ImpExpForm_t()

    ImpExpForm.Show()

# --------------------------------------------------------------------------
main()