What version are you using?
For V3 there is no support here you need to go sambapos.org
Most people here havent even used V3 and are working on V4 and V5
For V4 i dont think that can be done, i think the resources we need to do this were implemented in V5
For V5, yes this is possible by creating a custom table screen or editing the default screen. You can add customer name, balance etc to the button and there are also more formatting options for those buttons
For V5 this is the tutorial you need to read, it shows you exactly how to do what your asking, hope this helps 
Changing Table Button Captions