Hi Andreas,
I believe with the current implementation for Windows "Static" (pool/manual) will always configure gateway on the primary NIC, but not for the secondary NIC. This is implementation detail and may change in the future. For Linux this is probably not the case, I would have to check.
If you really want Static IP but not gateway, I would suggest to consider using your own pre-/post-customization script for setting up network in combination with OVF properties (see http://blogs.vmware.com/vsphere/2012/06/leveraging-vapp-vm-custom-properties-in-vcloud-director.html) for providing values like IP.
/Andrii