Switches that claim to do VLAN but don't

Recently I discovered the Allnet ALL0478A 8 port gigabit ethernet switch, that apparently has support for configuration via serial console, trunking, mirroring and VLAN. At least that's what the specification claims.

Nice idea, I thought this would be ideal to save some more PCI slots in my server (why do computers always have such a little number of PCI slots?). I could just connect one [or two trunked] interfaces from the switch to the server, and then connect DSL modem, various internal LAN segments and the WLAN AP to other ports at the switch. The linux server would then provide different network devices for every VLAN tag I use

Nice thought, but it doesn't work. Apparently they advertise something like 'switch segmentation' as VLAN. However, this kind of fake VLAN has no relation with 802.1Q VLAN - and thus cannot send you packets including a VLAN header :(