We were having a lot of problems multicasting to 530s in our school district; even had HP techs out for a couple of days. I haven't tried it personally yet, but a colleague informs me that the latest NDIS2 driver supplied by Broadcom (v 7.11) resolves the problem, even under Ghost 7.0. The download is at Broadcom driver downloads

With this, you shouldn't have to use the switch workarounds -FFX and/or -FNI

Joe