To do custom development you need Visual Studio 2010. WebMatrix is only good for testing/trying out mojoPortal. When you install mojoPortal from WebMatrix you are getting it from the Web Application Gallery, the packages there are pre-compiled and contain no C# source code. WebMatrix is sort of a development tool but it is optimized for Razor Web Pages which are not really compatible with mojoPortal. It is still useful for local testing, some people install locally in webmatrix, create content and then use webmatrix to push it to hosting, though I'm not a big fan of that approach, I would just deploy it to hosting and make the content there.

See also:

• Getting the Code with Tortoise HG
• Understanding the Difference Between Deployment Files and Source Code
• Avoid Forking the Code
• Developer Documentation
• Building a Guest Book video series

Hope that helps,

Joe