[CentOS] Centos 5.2 on Vmware Server: Disk space not preallocated -> no disk found by installer

Hi folks

I am trying to install CentOS 5.2 in Vmware Server environment. In my
VM disk space is not preallocated for the virtual disk (dynamically).
The installer doesn't find the disk. When preallocating 6 GB there is
no problem.

See screenshot[0]

Any ideas?

kind regards
Sven

[0] http://bayimg.com/image/lamidaabe.jpg