I would like to incorporate this into Knime. Has anybody tried this or can give me hints how to to transfer the BIRT report into KNIME (don't know anything about BIRT so far)?
I haven't tried this, but it looks like you will just need to build your workflow in KNIME like normal. Then use the 'Data to Report' or 'Image to Report' nodes to 'share' data to BIRT.
Then click on the BIRT reporting view button, and follow the instructions on the webpage to generate the report.