@Carlos: It's not that "OutSystems doesn't allow the password to be decrypted", it's that OutSystems stores the password as a one-way hash, which is the safest way to store passwords that needn't be sent as plain text, like Nicholas needs.
@Nicholas: As for the original question, I'd advise you to google a bit, e.g. for 'storing decryptable passwords' (without quotes) or the like. Two-way encryption is a must, but of course more "dangerous" from a security point of view than one-way hashing.