What you want sounds complicated in any program, including the three you mention. Poser 5 does have the dynamic clothing and hair, but I understand they do not export to Carrara 2. Maybe the bridge between the three will be made in the future (there are rumours and promises around), but I think you should at least take the use of additional software into consideration, compositing software. If you are a beginner, it might be wise to start with simpler scenes, wishes and ideas. Otherwise you will be frustates long before your Posergirls are running around a campfire in the thunderstorm...