If MultiMAN doesn't work with this I doubt I'll use it, even if it can load backups without a manager. I like multiMAN. It's more than just a backup loader.
In fact, the only reason I think anyone would really want to use this FW is if they get the PS1 and PS2 ISO support in there from the cobra dump.
That is pretty bad news because not supporting MM will probably be a big deal breaker for me.