This might be a little bit brutal, but why don't you just use the SQL Ledger Tables and port the functionality of it into an OpenACS Web based package. After all, it is reknown to be a very good accounting software *and* this would prevent inventing the wheel over and over again. Last but not least, if you go down that road, you might even be able to get some cross support from the developers.
Alternatively, just install SQL-Ledger on AOLserver along with your normal OpenACS installation and let your custom code write accounting information directly into SQL-Ledger by just porting from PERL to TCL the necessary ::create and ::get API.
Either way, I know it might be tempting to start with your own Accounting System, but give it some thought if it the best you can do with your development power, taking into account excellent software like SQL-Ledger.
