These are the links for anyone interested:

hxxp://www.woodmann.com/crackz/Tutorials/Cp375i.htm
hxxp://www.programmersheaven.com/articles/userarticles/john/vbvm.htm

and here is the article I took that sentence from:

hxxp://members.v3space.com/blackfenix/wktvbdebug/tutos/vbcrackme10.html

void, from these articles it would seem that there is indeed no equivalent for a NOP mnemonic in p-code. But then you say that it "is/was unknown". Is it still unknown???

yaa