Gain of biconical antenna or dipole antenna with FEKO

Hi to all,
i have i BIG problem.
I'd like to simulate the gain of a biconical antenna with FEKO. I think howerver the problem is the same if i try to simulate the gain of a monopole antenna. I'd like to simulate a trasmitting antenna.

FEKO has the PW card that permit to simulate the real exitation of an antenna with a real generator with a specified internal impedence.
The PW card apply a voltage generator to (for example) a line segment; let me tell this segment the phase centre of the antenna. The two arms of the antenna are connect to the end of the centre element.
The question is: how i can simulate this situation?
Anyone of you have used the PW card?

Thanks a lot!