Save option for "Multi-pass image" doesn't appear

[edub]

when I have Corona render setting, I don't get the "multi-pass image" file save dialogue.  If I switch back to standard render, and check the "multi-pass" on the left column, then switch back to Corona, then it's there...

[edub]

nevermind - I guess multi-pass just needs to be active in the Corona Multi-pass first ;)