The Zipp attachment is the same thing. I'm pretty sure Zipp gets them from Silca (or they both get them the same place). If you turn the wheel so that the hose lays down without pulling the head around, you can do it without a hand on the head.
Otherwise its one hand on the pump, and one hand on the head. (which is where a Silca track pump comes in handy reaching high pressure one handed).
The Raleigh pump from CT fits in the opening and allows you to lock it down. It does put some lateral pressure on the valve stem, though so the danger is that it may eventually bend the stem or cause a tear, I guess. The benefit, of course, is that you can use both hands to pump and believe me the pump action is so crappy you'll need both hands!