well, here a few more question, just to know & stuff.
I was just wondering around how:

1) people develope a music software, and with what tools?
2) whats the difference for developing a musical software (DAW, or some other editing tool etc) compared to digital plugins?...
3) what kind of database or system is required to make such stuff like a vst?...

thanks for the info. always wanted to ask this one