(aa), (bb), etc. as numbering format?

Is it possible to set automatic row numbering to use the format (aa),
(bb), (cc), etc.? Setting (a), (b), ©, etc. is no problem, but I
can’t seem to figure out how to get the double-letter format (which
is, by the way, used by some federal statutes, and it would thus be
helpful to be able to reproduce in OmniOutliner). Thank you.

– copied the question fromt he old blog, as I have the sam eissue/problem
(http://forums.omnigroup.com/showthread.php?t=3065)

Any help on that issue? Still looking for help. Thanks!

Answer from the Support via E-Mail:

"There isn’t a way to do custom row numbering (like aa, bb, cc,…) aside from changing prefix/suffix. I will add your request to our development database so that the team knows you would like to see the double letter numbering. We can’t work in every feature that our users suggest, but we really appreciate them, and we can promise that each suggestion will be read and considered.

In the meantime, the numbering would need to be manually added to those lines. "