QOS quality of service - 'Service Priority' fields empty ?

I am trying to setup QOS for multiple xbox's in my home.

I read that the best option is to enable UPnP , assign manual IP to each XBOX and enable QOS by adding a Service Priority for xbox live port 3074 ?

When i goto the router interface i can select from the pull-down list of "Service Priority" entries, but they are all empty ?

i.e. the xboxlive entry shows as"xboxlive 0 - 0" , does that mean port 0 to 0 , or in other words, un-defined?

My question is, are these pull-down entries supposed to be pre-defined or am I supposed to edit one after adding it ? How do i even edit one from the drop-down list ?

can someone explain how i am supposed to add an xbox live entry in service priority ?

thanks