Hickory: First of all, back up your input.settings somewhere safe in case this goes wrong. Second, I've not tried this personally, so don't know what the result will be. Ok, here goes:
Find the sections
[BASE_INTERACTIONS_KEYBOARD]
and
[BASE_INTERACTIONS]
Now replace appropriate IK_E= entries to IK_NumPad1, IK_NumPad2, IK_NumPad3 etc.
Thanks I've given it a go, but I can't find any appropriate corresponding entries. I'm needing like for just Dialogue IK_Numpad1 . THe base intereactions govern the E key for most confirmation type keys. Thank you though, I'll keep looking! :)
ps. I can't find that IK_1 anywhere that might govern dialogue keys. Perhaps this is not possible.