Hi can anyone advise whether it is possibkle or not to use the SIs as you would use a soft synth (i.e. as a sample that is played via  a midi note) or are they purely for creating loops to be inserted into songs?
 
many thanks

The Studio Instruments ARE softsynths - I don't know what you mean by creating loops to be inserted into songs.  do you mean the MIDI loops?  if so, you don't have to use the MIDI loops, you can create your own MIDI to trigger the SI softsynths by clicking with the mouse in the PRV or the Staff View, or you can use a keyboard or MIDI controller to record notes in the track to trigger the softsynth.

Hi I tried to load the Studio Instruments Drums into a project and i could get midi notes to play the drums but only the standard kit. I cannot figure how to change it unless there is only one kit in the SI Drums supplied with MC6.

Click in the window where you see [default.prog], not PRG>.
You should see a drop down list to select from.
Some of the variations are fairly minor, but there are differences.

Thanks - they are slight changes to the sounds the drums make but not kit changes - for example there was nio electronic kit there.

That's true. There is no electronic kit in SI Drums. It is a fairly basic synth/sampler and offers variations on an acoustic kit.
You might want to check KVR-Audio. They list numerous VST synths, which would be compatible with MC6.
You should find several that have electronic patches, 808. etc.

yeah, there's not a big variety in SI drums.  it was free with a $50 DAW, so you can't expect anything really great for that price.

check into toontrack EZ Drummer and expansion packs.  there are often sales on EZD for about $80 and often sales on expansion packs for $40 (50% off normal retail).  EZD is fantastic, IMO.  best drum software I've used!  and I know there's a really good electronic expansion kit for EZD ('cept I don't have that particular one because I don't do anything which would need them).