Hi Frank,
It is a bit complicated and the result may not be as linear as an encoder so you should decide it you really wish to do this.
Kanalog can not really output points fast enough to generate a sine wave at a high frequency, but I think a square wave should work ok. Especially if it is smoothed some.
The DACS can not drive a 20 ohm load directly. The Kanalog FET Drivers may work. Here is a description of how it was done with our older KMotion board:
http://dynomotion.com/Help/Resolver/Resolver.htm
http://dynomotion.com/Videos/Resolver.wmv
Regards
TK