Change task server on a site when PXE booting.

Hi there

We're running SMP 7.1. On our main site we have two servers, both have Task server installed.  One is called NS and the other WF.

When PXE booting machines, the %taskserver% variable always points to the NS server. How do I get it to use the WF instead?  Our image file is on the WF and for some reason this doesn't get replicated over to the NS so all our imaging is failing right now.

Some articles mention a Site Management section under Notification Server > Site Server Settings in the console, but I don't see a Site Management section.

Any ideas please?

Thanks.