Hi Vitaliy,
Been a while since I worked with that BAPI, but one thing I do remember is that it was just about the only BAPI that had good documentation. GM_CODE and MVT_IND were part of what needed to be set for use in MII. But GM_CODE was not the movement type. GM_CODE was a 2 digit code. I remember only using 02 and 03, but don't remember the specifics. MVT_IND was set to B or F and again don't remember the specifics except I think that was only for purchase orders (Back or Forward) which was whether it was being received or being fulfilled. Check out the documentation. It was all there.
Regards, Mike
SAP Customer Experience Group - CEG