How do I get absolute urls when inserting images or links to files in content with TinyMCE

I work in a multi-context setup in Revolution 2.2.2-pl, and had tried various solutions to no avail. (Also several have been found in this forum).

All images and files are under web context, and I need urls to be absolute, so the resources are working in other contexts. (The other contexts are subdomains and domains).

Does anyone have a bullet prof solution, and who can tell me which context settings, system settings - or plugin properties there are needed for it to work.

I've set up other sites in earlier versions of the Revolution, where I got it working, but this time it will not succeed. And I think I'm in a need for a clean start or a new head... ;-)

Thank you in advance!