I put it in the body, and the response shows:
["Diamar_USPS_FullResponse"]=> string(170) " 80040B1AUsername exceeds maximum length.USPSCOM::DoAuth"
This means the USPS username you are using is not being accepted.
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.