fstab mount shares on wifi network

[Firesam]

How can I add an entry to fstab that mounts a samba share that is on a
wireless network. The problem is that the network is not available until
networkmanager connects to the lan. That only happens after I login to
unity with my password. I dont think _netdev will help in this case. Is
it smarter to use a script on connect to the network that will 'mount
-a'?