Alteration of a custom field..turning from a text input to a file upload

[meshroom]

I'm having issues trying to alter the code of custom user fields. I've modified one of the customfields in the database to accept binary data, and i'm trying to populate it by changing the corresponding text input custom field to a file upload field...but I just can't get my head around the code. I've made a seperate little app that will do the job but it would be really nice to have it integrated into the main file upload/edit pages. If anyone could give me any pointers (such as which elements/blocks in the appropriate pages to modify) or know of an existing hack that does this, I would really really appreciate it. Thanks!