Cordovox1
Arrangements A, B and C and D are mapped to Fills 1, 2, 3 & Break and Ending 1, 2 and 3, so depending on which is lit before you press FILL or END, that is the one that will be played.
No Rhumba or Bolero? There should be a Bolero in your Preset styles (#13) and a Rhumba Mix (#78) and Rhumba Dance (#79) ... then again I might be wrong on this since my unit is slightly 'different' from yours!!
As for your favourite styles from the X4 - simply copy these to FD and copy into the STYLES folder of the Midijay. These should work ok for you.
Thanks,
AJ