Enhancing Weapons

Would it be possible to make it so that you can enhance items that have non standard damage types on them? For instance, my rogue is using a sword called Backstabber which does negative energy damage and is on hit level 5. Currently, I can pay to increase the enhancement bonus, but there is no way for me to increase the on hit level. I really like the sword, but it will be pretty useless at higher levels. I don't want to be able to create weapons with these non standard damages (negative, positive, divine, etc) but it would be nice if I could at least enhance the on hit level somehow, and makes finding and enhancing those types of weapons more special i think.

Nuli

I was planning to increase the number of special weapons in the module, so that you can find a more powerful one similar to the weaker one you have. I still haven't finished creating all the special weapons.