nm-connection-editor has support for configuring static IP information. Is that not working for you?
Certainly could not find anything on the network config dialog available on the live CD image. Maybe it is there now after updates, but I needed to config the static IP to get updates :-).
Try again if you have a moment. nm-connection-editor (provided by NetworkManager-gnome) is available on the live image, and should allow you to configure a static IP connection. If that's failing, that would be good to know.
So here's what appears to be happening:
Using the livecd on a usb stick, there was no ifcfg-em1 file created.
The only app that appears in the control panel is not nm-connection-editor but something that calls itself "Network Settings" (or something like that anyway).
That app has an Options... button which is, apparently, always disabled if there is no matching ifcfg-whatever file.
If I make an ifcfg-em1 file, the Options... button becomes enabled, and when I press it, it does appear to bring up an app that looks a great deal like nm-connection-editor, but there is no GUI way to get there given the default configuration you get with the live CD.
If I manually run nm-connection-editor from a terminal, I can create the ifcfg file, so there doesn't appear to be any reason to have the Options... button disabled.
A separate issue is that nm-connection-editor has one of the most screwy interfaces I've ever tried to use to fill out fields in a form. If I type the IP in the first field then hit TAB (the most natural button in the world to hit to get to the next field), it erases the IP address I just typed while moving to the next field. Apparently I have to hit return rather than tab (but I'd expect hitting return to be like hitting OK or Apply).
All in all, just editing the ifcfg file is simpler :-).