Storage vMotion won't move custom rom

Hi guys/gals,

We're using a custom bios rom by adding the line in the vmx:

bios440.filename = "custom.rom"

When I storage vMotion one of these machines it will timeout. When I storage vMotion, go to the target datastore and upload the custom.rom, storage vMotion will succeed. Is this just a limitation of Storage vMotion?

Using:

vCenter 4.0.0 Build 208111

ESX 4.0.0 Build 244038