GPP Drive Map done but not shown in Explorer (2K8R2 TS)

Hello,

I'm using a GPP to map a network drive.
I've turned the logging on like mentioned on this site: http://blogs.technet.com/b/askds/archive/2008/07/18/enabling-group-policy-preferences-debug-logging-using-the-rsat.aspx

When going thru the logs it works

2013-03-07 16:34:07.319 [pid=0x480,tid=0x5f8] Handle Children.
2013-03-07 16:34:07.319 [pid=0x480,tid=0x5f8] {935D1B74-9CB8-4e3c-9914-7DD559B7A417}
2013-03-07 16:34:07.319 [pid=0x480,tid=0x5f8] Starting class <Drive> - G:.
2013-03-07 16:34:07.319 [pid=0x480,tid=0x5f8] Set user security context.
2013-03-07 16:34:07.334 [pid=0x480,tid=0x5f8] Adding child elements to RSOP.
2013-03-07 16:34:07.412 [pid=0x480,tid=0x5f8] Set system security context.
2013-03-07 16:34:07.412 [pid=0x480,tid=0x5f8] Set user security context.
2013-03-07 16:34:07.412 [pid=0x480,tid=0x5f8] Properties handled.
2013-03-07 16:34:07.412 [pid=0x480,tid=0x5f8] RunOnce value created [SUCCEEDED(S_FALSE)]
2013-03-07 16:34:07.412 [pid=0x480,tid=0x5f8] Handle Children.
2013-03-07 16:34:07.412 [pid=0x480,tid=0x5f8] Set system security context.
2013-03-07 16:34:07.412 [pid=0x480,tid=0x5f8] EVENT : The user 'G:' preference item in the 'TEST_USR_DRIVE_MAPPINGS {0B569965-E7FA-4D23-ACE6-05BF139CF0BE}' Group Policy object applied successfully.
2013-03-07 16:34:07.428 [pid=0x480,tid=0x5f8] Completed class <Drive> - G:.
2013-03-07 16:34:07.428 [pid=0x480,tid=0x5f8] {935D1B74-9CB8-4e3c-9914-7DD559B7A417}
2013-03-07 16:34:07.428 [pid=0x480,tid=0x5f8] Starting class <Drive> - H:.
2013-03-07 16:34:07.428 [pid=0x480,tid=0x5f8] Set user security context.
2013-03-07 16:34:07.428 [pid=0x480,tid=0x5f8] Adding child elements to RSOP.
2013-03-07 16:34:07.443 [pid=0x480,tid=0x5f8] Set system security context.
2013-03-07 16:34:07.443 [pid=0x480,tid=0x5f8] Set user security context.
2013-03-07 16:34:07.443 [pid=0x480,tid=0x5f8] Properties handled.
2013-03-07 16:34:07.443 [pid=0x480,tid=0x5f8] RunOnce value created [SUCCEEDED(S_FALSE)]
2013-03-07 16:34:07.443 [pid=0x480,tid=0x5f8] Handle Children.
2013-03-07 16:34:07.443 [pid=0x480,tid=0x5f8] Set system security context.
2013-03-07 16:34:07.459 [pid=0x480,tid=0x5f8] EVENT : The user 'H:' preference item in the 'TEST_USR_DRIVE_MAPPINGS {0B569965-E7FA-4D23-ACE6-05BF139CF0BE}' Group Policy object applied successfully.
2013-03-07 16:34:07.459 [pid=0x480,tid=0x5f8] Completed class <Drive> - H:.
2013-03-07 16:34:07.459 [pid=0x480,tid=0x5f8] Completed class <Drives>.
2013-03-07 16:34:07.459 [pid=0x480,tid=0x5f8] Completed package execution.
2013-03-07 16:34:07.459 [pid=0x480,tid=0x5f8] Completed execution of apply package.

But the problem is, theDrive Map is not shown in the Explorer...

What is the easy way to find out what is preventing the drives from appearing?

Thnx!

Tim