Are there any API docs?

 Thanks.  I had found a lot of those sites already.  At the moment, I'm specifically looking for docs relating to creating files/folders via the API and can only find blogs (mostly from non-official Jazz sites) which use parts of the API which are undocumented (ex: IFileItem, IFileContent,Manager, IFile*, etc).

There is few official documentation available besides the JavaDoc. There is however the SDK and you can basically see the classes and the documentation if you followed  Setting up Rational Team Concert for API Development and Understanding and Using the RTC Java Client API. Even, if available for internal classes.

We who share looked into the SDK how RTC uses this itself. and some like Evan are developers. You will not find other documentation. So go with the posts e.g. https://rsjazz.wordpress.com/2013/10/15/extracting-an-archive-into-jazz-scm-using-the-plain-java-client-libraries/ or http://thescmlounge.blogspot.de/2013/08/getting-your-stuff-using-rtc-sdk-to-zip.html .

 Using the commandline is not an option.  I REALLY, REALLY, need to use the API to embed the solution into another application.