If your head is a player/party member head, you'll have to do a lot more work to integrate the mask into the model than just fixing the hook due to the way head textures and DS transitions work. Even if it's an NPC, fixing the hook is still probably more advisable.
If you already added the hook correctly via editing the ASCII, then all you need to do is load that ACII via KOTORMax and position the hook properly. Typically you'd want to import a mask model, make its OdysseyBase a child of the hook, select the Move tool, switch its co-ord system to Parent, then zero out its position. Now you can select the hook itself and manually move it into the right position, using the mask as a guide. I'd suggest using something like the Verpine Headband (I_Mask_011) rather than a full face mask. Once the hook is positioned, delete all the mask bits and then export the head model. Or you could even just set the co-ord system back to World or View and copy the XYZ values of the hook into your original ASCII.