[Freesurfer] aseg2feat and aparc2feat

Dear Freesurfers, I wanted to generate binary masks for areas found in the Freesurfer Color Lookup Table. For example, I wanted to use number 433, the Visual_V3d_l. I tried to use

aseg2feat -feat featdir --aseg aparc+aseg fslmaths -featdir/reg/freesurfer/aparc+aseg.nii.gz -thr 433v uthr 433 \ featdir/reg/freesurfer/Visual_V3d_l.nii.gz

The resulting image was empty. I was able to use aseg2feat for all subcortical regions, so then i used aparc2feat. However, this uses a different color table which is missing many of the regions present in the Freesurfer Color Lookup table that I would like to use.

How can I get area 433 (Visual_V3d_l) from the Freesurfer Color Lookup Table so I can later run fslmaths to generate a mask?

Thanks. Michelle