I have SI 2.x running against the virgo kernel runtime. The 2.x samples don't have support for OSGi built in.
I started out in STS with the Virgo web server runtime configured, and added the simplest 2. x sample (hello) project, then in Spring Tools menu, added OSGi Bundle project nature, targeted Virgo runtime, and built up the MANIFEST.MF (with added an activator):
Running against the virgo kernel is pretty much the same, without the web support. Here's how to upgrade the kernel runtime to the latest spring framework libs.