this is so extremely easy to do. the only way that you are restricted in adding more bytes to a section is if the raw data is greater than what is allocated in the VA. other than that, simply use winhex and go to the end of a section (get the offsets from lordpe or other pe browser) and do CTRL+0 (that's zero, not O) and put in however many bytes you need. when you're done be SURE to fix the raw section sizes and addresses thereafter. you're app will not run otherwise. if you want to add another section to the end of the PE, then umm, I'm sure you know how to do that, right?

good luck