To generate these subpages, I've used sgf2dg, and written my own plugin so diagrams can be output in Sensei's Library format. The perl module (Games::Go::Dg2SL) comes with documentation, so it should be easy to use.
First install Games-Go-Sgf2Dg (maybe using the CPAN shell), then either copy the Dg2SL.pm module into the proper perl module directory, or put it into a directory named lib/Games/Go/, then set (using bash syntax):
All you need to do then is to create your SGF files and then run
sgf2dg -converter SL -m 10 -n foo.sgf
This will create foo.sl. Just copy-and-paste the contents of this file into the SL page's textarea.
It'd be best to avoid marked stones and marked intersections because sgf2dg doesn't print them too well (or maybe it does and I've made a mistake with the SL converter). And remember that SL diagrams don't support labelled stones.
I've sent the plugin to the author of sgf2dg for possible inclusion in the CPAN distribution.