MPC2500 - Control Volume On External Keyboard/JJOS Upgrade

I'm pretty new to the MPC. I'm more of Gospel keyboardist and I use to hate on the MPC's back in the day, but I spent the money to buy one to see what all the buzz was about this drum machine and now I can see why it's such popular sequencer. Many of the functions are easy to use and the sequencer seems to be geared towards making drum tracks. I'm using the Akai OS, but plan to upgrade to the JJ OS soon. I just want to see what Akai OS can do first. I have two questions.

First Question:
I have a MPC 2500 as my sequencer for my Fantom x6. I'm guess that I'm missing something here because I can send program changes to my Fantom x6 to bring up the right patches, but the one thing that I'm missing is controlling the volume of the patches. Is there something I'm missing here?

Second Question:
When I upgrade to the JJ OS, are my sequences and songs (from the Akai OS) going to be compatible with the JJ OS?

Bump...If anyone knows the answer to either or both of my questions, I'd appreciate it. Thanks in advance...

you should be able to change velocity from the track level, if thats not working then;

is the fantom setup to recieve velocity changes?
can you change the level of any other external instruments?
are you connected MPC -> fantom directly without passing though any other midi equip?

jj- im prety sure but, try the JJ forum, theyll be able to tell ya.