I no longer have my BUD system, but when I did the setup I used was this:
2 2-way splitters with 1 power-pass leg and 1 non-power-pass leg.
1 2-way
DiSeqC switch. (or you can probably use a 22KHz or DC switch)
Put 1 splitter on each of your feeds to the dish. 1 on the
C-band and 1 on the Ku-band. The power-pass leads will go to your 4DTV system as you have it right now. The non-power-pass lead will go to the 2-way switch. The lead from the switch goes to your receiver card.
Your biggest problem is that you will not have control of your polarizer or your dish motor from the FTA card. You'll have to move the dish and set the polarization from the 4DTV.
This is a workable solution, but not an elegant one. As soon as possible, I'd start looking for a dedicated Ku dish and rotor if I were you. The family was never happy when I made them quit watching their TV shows while I searched for wild-feeds.
You could still use the BUD for C-band FTA feeds on those occasions.