I need to fix some options in php script

i have an Bulk Mail web application based on php, and i want to customize an options on it. when you want to send an e m a i l by this app you need to fill out some important information on header field like this [login to view URL] i will explain some header content Subject: [anl7] # e m a i l subject From: [anl7] <[anl7]('at')[domain]> # e m a i l from + e m a i l sender and this Tag [anl7] is a Random contain alphabet lower case + numeric and this other options of this tag random [a] : Alpha Random [al] : Alpha Lowercase Random [au] : Alpha Uppercase Random [an] : Alphanumeric Random [anl] : Alphanumeric Lowercase Random [anu] : Alphanumeric Uppercase Random [n] : Numeric Random when i send an e m a i l by this header to hotmail for example this's what i found in the e m a i l source [login to view URL] if you see this tag replaced by the same random "dpozxhm" on every place you put the tag on it. that good now look at return-path:<> cause his filed [login to view URL] is empty when i put this [anl7]('at')[domain] in return-path field and send a test this the result [login to view URL] the return path e m a i l have a different random from other so this's my problem i want the return-path field have the same random like other. and there's another tag [fname] doesn't work in return-path field and working in header field for security reason i can't give you the access to fix this problem but i know where excat the php script that you need to fix this problem so i will send you the two pages to check it and tell me your cost