[Freesurfer] mri_mask problem

Hello everybody,Sorry for the insistance, but I need to solve this...

I'm making some manual segmentation changes in the brainmask.mgz and using mri_vol2vol and mri_mask commands to apply these changes to the rawavg.mgz, the output from the mri_vol2vol looks perfectly normal,and retains all changed made by me, but when I use the mri_mask command over the rawavg.mgz no segmentation seems to be donne in the final output file. Does any one has an idea of what could be wrong? the commands after manual corrections are: mri_vol2vol --mov brain.mgz --targ rawavg.mgz --out brain2raw.mgz --regheadermri_mask rawavg.mgz brain2raw.mgz outbrain.mgz

Thanks in advanced,Gabriel