Word VBA fails pasting into Footnotes

Question

I am trying to copy a piece of formatted text from one (rtf) document into a field in a Word document. In Word2003, copy and paste via the clipboard works, but in Word2010, if the target range is in a footnote then the Paste operation fails (actually does nothing but does not give an error). In Word2010 however, using PasteSpecial works, but in Word365 that fails too.

This is my code:

If IsObjectValid(extIndex.getHeadingText(i)) Then
                        extIndex.getHeadingText(i).Copy
                        fieldCode.Collapse (wdCollapseEnd)
                        fieldCode.Paste
                    Else

Is there some other way to do this or am I doing something wrong?