SQL Express 2005 SP2 And Local Service Account

I'm trying to do an unattended install of SQL Express 2005 SP2, and specify that the service runs under the Local Service account. Prior versions of SQL Express worked fine.

With SQL Express 2005 SP2, however, the install fails on XP Pro SP2. It *does* work on Winows 2003 Server.

Here's the command line I'm using:

SQLEXPR.EXE /QB ADDLOCAL=ALL INSTANCENAME=FOO SECURITYMODE=SQL SAPWD=BAR SQLACCOUNT="NT AUTHORITYLOCAL SERVICE"

It fails at the end of the install, saying it can't start the service. If I use "NETWORK SERVICE", it works fine, but that's more privileges than I want the service to have. Is there something else on the command line that I can try to get it to work?

Is this even supported?
-Dave