Hi hearvox, I was using the Exec PHP plugin, to put PHP in the posts, but I followed your line of thought and moved it to a file and it worked.
However I must admit that the plug in Formidable Pro Forms -that Radices pointed out- is a great option that will make my work a lot easier, so I think I'll try it for this job. Deadlines are killers.
How do I give my approval to the sounds pieces of advice you gave me guys?
Thanks