Here is some additional information regarding VLAN configuration on the PMP450 series.
http://community.cambiumnetworks.com/t5/PMP-Getting-Started/VLAN-Engineering-and-Design/m-p/39292/highlight/true#M46
http://community.cambiumnetworks.com/t5/PMP-Best-Practices-and-Examples/How-to-configure-PMP450-VLAN-tagging/m-p/51009/highlight/true#M19