Martin,
I run into this all the time when teaching the LabVIEW courses.
Although you can select the channel names you have created from the drop down menu, it only allows you to select one. What you need to do is manually type in the additional names (with a comma separating each name). In order to do this, make sure you have right mouse clicked on the control and Allow Multiple Names is checked.
Hope this helps.
--Eldon
PS. You have probably noticed, but you can't combine the names and the numbers, i.e. 0,1,temp,3 will give you an error.