Good news from Cold Land of Bears, Balalaikas and Vodka :)
Privet from Russia, pals ;)

Problem with attachments for tasks solved easily and elegant

1. Link your RTM account with your Gmail account.
2. Log in Google Docs
3. Make a new collection in Google Docs for documents must attached for a new task in RTM.
4. Copy address link for the collection created in Google Docs (see p.3).
5. Add a new task in RTM
6. Use" URL" field in task's properties and paste there address for collection from p.3
7. Fill the collection from p.3 with ANY documents for your task (not more 8Gb of "not-google" docs and unlinited "google" docs)
....
MAGIC! All documents for the task are in the one Google Docs collection :)

BONUS for Android users -- you may use RTM app and Google Docs app in your phone.