I can think of a few ways to do it.... depending on what you will do with it (as to whether you are storing a value to read or process later, like a "password keypad).
A couple of quick ideas to research:
- Use DHTML (Javascripted layers): clicking an image in layerButton1 causes "1" to appear (onClick event in the Actions menu)in layerScreenDigit1 (which could then be parsed and stored as a variable to be used for whatever) - visit Macromedia's knowledgebase for info on automatically populating text in layers
- As above, but use images instead of text in the layers. This would be right for an LCD effect, etc.
- Do as above, but with a more "powerful" technology, such as Perl or ASP
- Use Flash.
Good luck!
CG