Part 1 can be found here.
Part 2 can be found here.
Previously, I've demonstrated how we can set up a Source Control Provider in OnTime, and add a link between a defect in OnTime and a file under Source Control. Now I'll show you the fun part, how to check files in and out through OnTime.

Here we see our defect with the file link that was created last time. Now, you can click on the "check out button", and presto:

We see now that OnTime is telling us that the file is checked out. Let's go edit it.

We've edited our file and saved it, so let's come back to OnTime and check it back in.

After we put in any checkin comments and click on "Checkin", the file is now checked back in to Vault. However, we may need to see what the history of the file as well. Through OnTime, we can do this also:

Click on "View History" and the history for the file is brought up (you can also select a version of the file and click on "View" to see the file as it existed at that version):

Here is Vault's history explorer for comparison:

We've also added the SCM integration into OnTime for VS.Net:

That just about covers everything as far as SCM integration goes. As always if you have any questions or comments, please let me know.