hmm, i'm not sure what that line would do, but try messing with 
  powerSucceeded = 0; //always 0 for nonhold powers  
 line and   
 self->client->ps.fd.forceButtonNeedRelease = 1; line, i believe those 2 should get you to what you want. and instead of commenting out try changing 
 WP_ForcePowerStart( self, FP_GRIP, 1 );  
 to 
 WP_ForcePowerStart( self, FP_GRIP, 0 ); 
 anytime bro :), btw, i've searched the internet and all my help has been through contacting good modders, rove searching through this forum or going to 
http://www.planetquake.com/code3arena/)