I don't have Sibelius, but I have Notion 3.. And as far as I know, rewire only allows audio to be passed through - for example, notate in Sibelius, pass the (Sibelius) audio to Sonar for mixing / applying other effects. So, I'm not sure how do you activate Session Drummer 3 inside Sibelius ?
Do you need to program drums via notation ? Is notation required at all ? How about using Sonar Step Sequencer ? I'm asking these because from my understanding of reading your posts, you would like to use Session Drummer 3 / mix it in Sonar - so why use Sibelius to input notes ?
You can also print drums notation from Sonar (using Staff View) after programming the parts using Step Sequencer - or export the midi out into Sibelius for further printing.