Can't get VLAN to work

Question

Hello,
Maybe I'm missing something elementary.. this is my first time trying this out and just can't get it to work.
I've got an xserve on a netgear smart switch on port 13. The netgear is hooked up to two different networks (204.x.x.x via port 1 and 128.x.x.x via port 2), and I have 2 VLANs setup on the switch (vlan 1 has port 1 and port 13, vlan 2 has port 2 and port 13).
The xserve's interface that's on port 13 has a 204 IP and works wonderfully on the 204 network. I then tried to setup a VLAN via sys prefs network and that appeared in the network configs list, and gave it a 128 address. However, even with all the right settings, it won't show up at all on the 128 network.
Is there something basic that I'm missing?

Answer 1

Oh, thats not exactly what I meant
Basically:
The server serves Web and QTSS via 204 to the world via en0.
Then, there's 5-10 machines or so on 128 (and 1-2 on 204) that sync over 3TB of data to the machine via 128 (this sever is the only one we have on site that has raids hooked up to it, so its the central data storage so to say), so en1 is pretty much completely saturated between 12am and 8am (and during the day when there's a lot of new work going on). Originally we used to do this over the primary web interface and all the web traffic would suffer (and especially qtss... we'd start getting disconnected errors all over the place when we started up massive copies).
Half of the machines are 204's and the rest are 128's, which is why we want the ability for en1 to be able to talk locally to machines on either 204 or 128, without having to interrupt the main interfact (if that makes any sense). Does that seem like a sensical solution?
If it also helps visualize a bit:
I only have access to register 8 machines on the 204, and TONS on the 128, but im not allowed to serve .com traffic on 128. Technically, the 128 does talk to the 204 locally on location, but its done through a nasty switch and we dont see much higher than 10Mbps tops.