So here is one way to do it with just the BIAB drum real tracks. It takes some work and a lot of time but if you don't move the position of the tracks the timing part shouldn't be an issue.

In BIAB first pick what drum real track you want to use for the initial style. Generate the track and render the WAV file and drag to the first track of your DAW of choice. This is your base guide track. Go back into BIAB and repeat the step but each time before you regenerate add markers at various points to get the different fills to generate. Also switch out to a similar real drum track just to get some variance in the fills. The idea behind this is to end up with a dozen or so (yes it sometimes takes that many) individual WAV tracks in your DAW that have as many variances as you can generate including other styles.

It is time consuming but once your in the DAW your creativity is the only limit. Start at the bars in the song you want the solo at. Audition the tracks one at a time at first then start auditioning another or several at the same time. You will start to get a picture of how you want the solo to flow. Then its a matter of splitting the sections and pasting into the base track.

If your DAW has a snap to grid feature you should be able to slice, dice and splice with out to many timing issues. If you have a nudge feature you can nudge the clips just a bit forward or back to try and humanize the sequence a bit more. You can pull bits and pieces from anywhere in the rendered tracks in fact if the solo is nestled as a bridge don't be afraid to try a fill that was generated in a verse.

You wont get a Neil Pert or John Bonhamm drum solo but you can create some really nice 8 and 16 bar solos and its completely your creation. There is some satisfaction in that and makes the effort worth it in my opinion. I do the same with the guitar soloists. The only draw back is that if you want to use it BIAB you will have to import it into the audio track. I've never tried that so I don't know what issues would result from that. Also if you use several real track styles there may be some sonic sound differences.

One other trick that works occasionally is to build 2 main drum tracks and overlay the fills or the move them a half beat. You can get some really busy solos that sound like roto toms and double kick drums. Careful its easy to go too far and then it just gets messy.

Again this is just one way. This one works for me but some others may have a different way.