Hi,
Unfortunately the documentation for sap log book setup is not very good. The example implementation is fully loaded with features, however there are no detailed instructions on how to build a simple log entry subscreen and get it to store and return data. Me and our programmer have spent a week trying to overcome a seemingly simple abap error. We are now trying to take pieces from the example implementation and try to build ours. If we make a breakthrough I will post our solution.
Good luck,
Al Horvath