You’d just use the standard tools on the left hand side toolbar , the arrow, rotate scale etc..
I’m not sure what’s happening if you can’t select and move anything with the default move tool.
as long as your in UV mapping mode and can see the split screen with the UV Grid, you should be able to double click on any part of a mesh “island” to select that,. then click and drag on an edge or vertex to move it,.
you can also click to select a single vertex or edge an drag it to move that point or edge, for example if you were fitting a model to an area of an image.
you can also hold Ctrl or Alt to restrict or constrain the scale or movement of the tools
As for CS5 , you’re ahead of me,.. I’m still on CS4, but it also has the ability to open objects and create uv’s (but it’s slow as treacle for me, so I don;t use it ) maybe CS5 is better.
Once you’ve UV mapped your model in Carrara,. you can either click on the “display” tab in the modelling room, and click the “Export” button to export the Wire-frame (black and white) texture map of the mesh UV Grid ( to make a UV Template) ..see pic.
then open that in photoshop and use it as a guide to laying out your textures,.
You could Paint directly onto the model in Carrara, using Images, textures, or colours, using a range of shape brushes.
You can work in a PSD file, ,.. then open that in photoshop if you wanted to add other details or change anything
Click thumbnail to see full-size image