mkamoski,

You are making some assumptions that could end up costing you alot of money.

1. BIAB does not have sound patches included. See Flatfoot's response above

2. You don't need to limit yourself to standalone soft-synths. BIAB is designed to use soft-synths, you just haven't figured out how to configure it correctly yet.

In fact, with all due respect to zero zero, I would suggest simply laying that suggestion aside for now, since what you really want to do, so it seems, is to use the sounds while using BIAB. Utilizing a standalone synth in that case makes things quite a bit more complicated.

But, perhaps you are looking to simply 'perform' using the digital piano as what would be called a 'controller' and the synth inside the computer responding in-kind. In this case, either looking for standalone versions of synths works, as does jford's suggestion of using SAVIhost from Hermann Seib, which simply 'wraps' the .dll of the VSTi into an executable miniature 'host' program.

There are loads of free VSTi that do what you are looking for. Some are better than others.

In my 'go to' list of soft synth providers are the following developers and downloads:

Minimouge VA - great lead mono synth emulation of a minimoog: http://home.no/gunnare/downloads.htm
Genuine Soundware's Donationware bundle - Organized Trio is a great B3 emulation, the various electric piano emulations are also great: http://www.genuinesoundware.com/?a=showproduct&b=37
Feldspar - great virtual analog synth with tons of modulation capability and FM between oscillators as well as ring modulation: http://www.contralogic.com/vst-plugins/feldspar/
sfz soundfont player - good for general midi and other acoustic sample based sounds: http://www.cakewalk.com/Download/sfz.aspx

With these alone, you can cover most of your needs. Cost: Free (with some mental elbow grease to get them loaded properly into BIAB)