what guestOS is that vmdk coming from ?
if windows7 or 2008 you may need to specify the partition you want as an extra argument to vmware-mout
both OS usually create 2 partitions - the first one is a small 100MB partition.
Also I dont think that you will see the mounted drive in diskmanagement.
Make sure you run vmware-mount as admin - and then use the same cmd to start explorer on that drive