You shouldn't need to edit any apache fragment as the server is, by default, already setup to use ssl certificates. The only difference is where the certificates are stored on the system.
On SME, your key & crt files are stored under the following directory /home/e-smith then key or crt for the relevant files.
Just run through the procedure from the CA but name your files <nameofserver>.<domainname>
For example - my server is called mail (I know it's a cr*ppy name) & the primary domain is hspencer.co.uk.
My crt & key files are named mail.hspencer.co.uk.crt & mail.hspencer.co.uk.key. If you follow the naming convention then you don't have to edit any apache fragments.
I followed a great how-to by Greg Swallow, only I bought my certificate from freessl when they were $20 for a year.
The how-to can be found here
http://forums.contribs.org/index.php?topic=24067.0Hope it works out.
Howard