Hi Lorenzo,

I was trying to do this too, and used:

1. mri_surf2surf --srcsubject fsaverage --trgsubject $s --hemi $h
                        --sval-annot $h.yeo.annot
                        --tval $SUBJECTS_DIR/$s/label/$h.yeo.annot

2. make yeo.gtmseg.ctab - I copied gtmseg.ctab, pasted yeo network ctab at end (offset LH by 1000, offset RH by 2000) and added column with tissue type (1=cortex)
        ie.    1001    lh_17Networks_1 120  18 134   1

3. gtmseg --s $s --o yeo.gtmseg.mgz
                        --ctx-annot yeo.annot 1000 2000
                        --ctab yeo.gtmseg.ctab

4. mri_gtmpvc --i pet.nii.gz --reg template.reg.lta
                        --psf FWHM --default-seg-merge
                        --auto-mask PSF .01 --mgx .01
                        --seg yeo.gtmseg.mgz
                        --o yeo.gtmpvc.output

This worked for me, but Doug and others can tell you if this should be done differently.

Best,
Sara