One method that I can think of is to find a font that has the required format and create a special list to use the font for the numbering.
I may have something lying about - will have a look and if I can find something will post back
If not there are many sources of free fonts on the net
Edit - I've made a workaround using the Wingdings 2 font which will give you 0 to 10
Have attached a doc file so you can see what I have - it's not perfect as the wingdings2 font does not map accurately and you need to start numbering at "f" but it may help or at least give you furrther ideas Number Test.doc