Hi Malte,
I think our posts crossed.
Let me reasure you that we're not going to go for a Yet Another Accounting System. Instead, P/O captures costs over the web and allows for the "controlling" stuff (redistributing costs to projects and customers) that is needed by project-oriented organizations (and not provided by SQL-ledger).
The idea is to export these items afterwards to SQL-ledger or similar packages (Quickbook, Conta-Plus, KHK-Kaufmann, ...) to facilitate the creation of balance sheets and income statements are required legally.
I'm already looking at the OfBiz and SQL-Ledger data models. It would be really cool to run OpenACS and SQL-Ledger on the same server...
Frank