Using "Fax Number" field as "Tax ID Number"

One client of mine needs a field for "Tax ID #" on the registration form. I don't want to try the add-on called "Additional Customers Fields" since it doesn't seem to be stable. So I'm considering to change the "Fax Number" field to "Tax ID #". Would there be any problem with that? Can someone give me some idea what files I would need to alter in order to use the "Fax #" field as "Tax ID"?

Thanks in advance for any help!

Have you looked at this? I haven't used it.

http://www.zen-cart.com/index.php?main_page=product_contrib_info&products_id=1188

Thank you very much! I think this would be the one to try. Unfortunately this mod is poorly documented. I would need to spend lots of time to compare the files because I cannot simply replace them..

Thanks again for the tip!

check our site: https://www.mundounik.com

I did exactly what you want. Changed the language files to use ID number instead of Tax. After that made the field obligatory and thats it...relatively simple (now that I know how to do it) :smile: