Hi There
If you can afford to spend a bit more, have a look at the Wersi Ikarus http://www.wersimusic.com/organsx.htm and http://www.wersi.net/html/ikarus.html as it has Real time controls a plenty, (Including Transpose) it can also play Giga Samples so you can really get a Jazz Piano, + you can also use VST instruments, which means that no mater what instrument you want, you will find a VST instrument Emulation. (NI’s B4 being the best Hammond B3 Emulation there is, although the one included in the Wersi comes close)
Hope this helps.

Bill