Vlan through EnGenius

Hi friends: I have the folowing problem. I have a link with two diveces EnGenius. Through him, go data and Internet. The problem is pass through the link a Vlan.

There is no problem with other kind of trafic. Anyone worked with a Vlan through a link EnGenius?

Thanks for any idea.

It could be that EnGenius does not support large enough MTU for VLANs