Disklavier

Hi everyone, I'm new to this group, having just purchased a used 
MX100B.  I have a problem that I thought maybe someone in this group 
has a solution for.  I would like to use this in a live performance -
 however I need to have the keys to some of the songs transposed for 
the singers.  I am not sure if the MX100B will "transpose" on the 
fly, so instead I had the idea that I would use another Yamaha P-150 
Electric Piano and hook it up through the MIDI ports.  I was able to 
get it to work with one small problem.  Everytime that I play the P-
150 keyboard, there is a 500msec delay till you hear the 
Disklavier.  Is there any way to prevent this delay?  Maybe there is 
something I could purchase (like an upgrade) to prevent this delay?  
Any ideas would help?

Thanks.

--Jason