if only it was that easy...
Visual Basic is the easy part, de-compiling the composer format is the hard part... too many variables.
In years gone by I used to change all the hex identifier codes of the organ and piano disks so they would work on the keyboards, also enabling the loading of all the keyboard presets that would not load from one series into another, thus getting every preset style from every KN ever made, but never tried programming composers by trial and error.
You need to talk to Thomas at
http://www.thkmcs.de/ because he managed an editor for 3000 format.
Also EMC software at
http://www.emc-software.de/taste/ has software to convert midi to composer direct, but not in a direct format for your piano.
However no-one has cracked the 6000 compression yet, and we now have 7000 format to look forward to...
the 6000 series has a sequencer to composer copy function that enables you to make composers out of suitably prepared midis.
if you manage something for your piano I send you best wishes and wish you the very best of luck.