BIG-IP LTM VE and VMware ESXi

If your internal and external are in the same subnet mask and broadcast domain, then you don't need both vlans configured on the VE. You can just give one side a dummy value to get through the set up process, or you can exit the set up process and manually configure the vlan, self IP, etc. However, if your internal and external share the same address space, but are in different broadcast domain, and should be separated at layer 2, then you may need to use Route Domain on LTM. Look for Route Domain on F5 knowledgebase site.