[otrs] Time Accounting report

Hello, I use OTRS 2.1.4 on SuSE 10.2 and I want to create a report which calculates work units spent by agents working on tickets with particular customerID during given month. Is it possible to create such report using report creation wizard or I have to do additional coding? In case I have to do some coding what is the way to integrate it with OTRS - I checked developer documentation, but it seems that there are some differences between 2.0 and 2.1 versions (Only 2.0 is available on the web site). Thank you very much Atanas Karashenski