Hey-
I'm not too familiar with Fruity, but I don't think it offers external midi control (just sync info?)
Does the 505 even have MIDI? If I'm familiar with the TR stuff, they just have CV gates control- you would have to get a MIDI-CV converter, and then get a MIDI sequencer- like Sonar, or even the new ACID, and then you're in business. As for finding the CV unit, good luck, I'm looking for one myself...