modify existing Thunderbird extension (Enigmail)

I need a plugin for Mozilla Thunderbird 1.5.x that does the following: -1st objective- When a new message is downloaded (either via POP3 or IMAP), before placing it in one of the mail folders (according to Thunderbird's filtering rules), the message is saved to a temporary file and an external program (as defined in the preferences hive) is called. The path to the temporary file is passed as an argument to the external program. The external program writes a single line to stdout. The plugin will open a Yes/No box and put the output of the external command inside the Yes/No box. If the user answers "Yes", then the message is regularly processed by Thunderbird filters. Otherwise the message is moved to a specific folder as defined in the preferences hive. This is quite similar to what Enigmail does when processing PGP signed messages: it executes an external command (see the ipc/ dir inside Enigmail) and shows an appropriate message to the user. The source code of this project will be released under the GPL, so you can take the code inside the ipc/ dir of Enigmail extension and use it. We will give proper credit to Enigmail, where necessary. -2nd objective- When the user opens an attachment, the plugin should save the attachment file in a temporary path and call the external program. The path to the temporary file is passed as an argument to the external program. The external program writes a single line to stdout. The plugin will open a Yes/No box and put the output of the external command inside the Yes/No box. If the user answers "Yes", then the attachment is opened as usual. If the user answers "No", nothing happens. ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Deliverables must be in ready-to-run condition, as follows? (depending on the nature? of the deliverables): a)? For web sites or? other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software? installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform Windows XP, Linux