My first post here at Presonus (I think).
I am not a Superior Drummer 3 owner but since there is no SD3 demo available maybe someone that has Studio One 3.5 and SD3 can answer this question I sent to Toontrack support.

Background - SD3 has a stand alone midi editor timelime. You can make tempo and time signature changes along the line. Here was my question followed by their answer.

"After creating a modified tempo and time signature in Superior Drummer 3, how do I export that information into my DAW. In other words, if I create a song with both 7/8 and 3/4 time signatures and varying tempo in SD3 how does my DAW know how to follow what I created? Do I have to use Rewire? Please advise. Thanks."

Toontrack -
"Hi John, Thanks for your email. There is not a way to export the tempo map from SD3 directly. When you export the MIDI created in SD3, it should retain the time signature and tempo data in that file. Some DAWs will ask you if you want the tempo and time signature data that is written to the file to be included when imported to the DAW. In our tests, we have not been able to get Studio One Pro 3 to ask if the time signature/tempo data should be included during a MIDI file import. We are limited to support we can provide for Studio One, so we cannot advise which setting would help keep the data written to the MIDI file."

Has anyone, who owns both products, been able to do this? Thank you!