I have a simple orchestration that takes a request message and calls a web service with parameters our of that reuqets (after doing some work on them and making a couple of checks).
In certain situations the orchestration needs to call the web service more than once - so I figured - theoretically, instaed of reaeating the web service call in the orchestration or trying to get it in a loop, I could simply create my own request message with the new parameters and call myself. classic recursion.
Only that BizTalk does not let you do this, and I suspect this is just a UI limitation - it is as simple as the fact that when you open the call orchestration dialog you see all the orchestrations in the assembly but "yourself".
If I had some time I would try editing the ODX file directly to get this to work just to prove whether this is just a UI limitation or not, but I can't afford taking the time now and anyway it would not be helpful as editing the ODX files is ALWAYS a bad idea!
(I've added a follow up on this here)