Just found out how to turn on vmware-tools clocking syncing from inside the guest, rather than editing the .vmx file on the host.
Once you have vmware-tools installed and configured try this:
/usr/sbin/vmware-guestd --cmd "vmx.set_option synctime 0 1"
To verify this has worked look for this line in the corresponding .vmx file:
tools.syncTime = "TRUE"
