Try forwardattachment plugin (see my signature for download).
Thanks a lot! That's it!
Have only two minor suggestions:
RC can't deal with eml, and attachments are opened in a local MUA. That is not a problem in fact, but after migration to RC users almost forgot how to play with MS Outlook
Other point is that attachment name is built of message subject, that can be (and mainly is, in my case) non-latin. As result we have attachments like that:
"Re:___________.eml"