Why can't I standby with a full drive encrypted laptop?

I've got a Dell Latitude e6400. It's got one of those nifty FDE (full drive encryption) hard disks that automatically encrypts everything on it. Every time I power up, I have to enter a username/password to unlock the drive before the computer can read or write anything too it.

The problem is that it seems to have forced me to disable 'standby' mode and always use 'hibernate' mode with Windows. I'm told that this is because the BIOS is only invoked for the FDE password on powerup mode for hibernate or cold boot, not for standby. I know for a fact that my old Dell D620 laptop used a hard drive password and always asked me for it before I resumed from standby, so I'm skeptical as to why the FDE drive requires it.

We use wave.com trusted drive software embedded in the BIOS of the e6400. According to this link:

http://www.wave.com/news/press_archive/08/081110_Seagate.asp

they DO actually support secure Windows Standby mode, but who knows what that actually means or whether it relates to the platforms that we are using. It does mention some comments about 'vulnerability of FDE and exposing encryption keys.' Based on that, I suspect there are issues related to encryption keys staying in memory during standby mode that could theoretically be stolen.

My biggest complaint is always 'security for the sake of security' without really understanding what the threats and/or risks are. Basically: do you know who you are protecting against? FDE and even hard drive passwords protect against removing a drive from one computer and using another computer to read it the data. Assuming standby mode works properly, you should still be able to protect the drive in low-power mode simply by ensuring that the computer comes up locked and requiring a user password when it awakens. I admit the possibility that there are some sophisticated software attacks that can be used against the live machine (assuming it is stolen while in standby mode), but I haven't searched for any. I imagine it's a fairly sophisticated attack and will NOT include the casual thief who steals your laptop and sells the drive ebay to Joe Dumass.

Questions to answer:

• What are the threats against FDE and standby mode?
• What are the threats against standby mode, in general?