Enabling Velocity Sensitivity on old Groovesynth via Sonar X1?

I have an old Groovesynth (Roland JX-305) that has some real basic drum sounds that I like to use on my tracks. However, changing velocities with Sonar X1 has no effect on the internal drum sounds of my JX-305. Another detail is that all the sounds I edited or created in my JX-305 cannot be accessed in Sonar X1 - seems I can only access the factory presets that CANNOT be edited/deleted, even on the keyboard itself. The Sonar X1 interface for the JX-305 is also very basic; 3-band EQ, cutoff/Resonance, volume and tuning but no velocity.

Is there any possible way I can apply velocities to the drum sounds on my JX-305 Groovesynth? I'd hate to have to copy the midi data into another track, find/load new drum sounds, re-assign keys... just to enable velocities.

Thanks in advance!

-Khalin