Hi Woland,

You'd have to either use a real amp, or have a stand-alone amp simulation program running at the same time as Band-in-a-Box. Your guitar would play through that amp sim separately from Band-in-a-Box, while BIAB plays.

Since Band-in-a-Box doesn't support input monitoring, that's the only way you can use an amp sim in real-time while using BIAB.

Alternately, you could open the song in RealBand, and apply an amp sim plugin to the "Input Monitor Insert" channel. This'll work as long as you're using an ASIO or WAS audio driver, with input monitoring enabled.

Thanks
Kent