iDrac6 - Unable to boot on Virtual iso file:

I have just bought 12 x T610's that I put around the country. I know I could call support about this, but I've tried and it doesnt seem that the knowledge concerning this was available when I called support:

The problem: I am unable to boot from virtual media (iso-file)

I'm not sure how to do this, but I understand that I need to start the remote console and select virtual media > launch virtual media.

Then I add the iso file I would like to boot from.

I've tried booting on it but it does not work.

When I try to Map the drive (still in launch virtual media menu) I get the error:
Drive Error
Either Virtual Media is detached or
Virtual Media redirection for the selected virtual disk drive is already in use.

I've tried this from dozens of different computers and it's no go.

As First boot device, I've tried Virtual CD/DVD/ISO but there's no go.

So. how do I mount ISO files and boot on them? The iDRAC is loaded from another server using IE8 on the same subnet as the server I'm trying to boot (gigabit). The iso file boots fine when mounted using vmware etc (190mb)