mapping pages into new address spaces

Hello, I am playing around some with L4 programming.  I have a  
question about initializing new address spaces.  I want to create a  
new address space, map some memory containing a program into it, and  
then start the new thread.  However, there seems to be a chicken and  
egg problem.  I can't start the new thread in the new address space  
until there is program code mapped in for it to run.  But the only  
way I can map pages into an address space is to have code running  
there that can receive the MapItem IPC and accept it.

Here's the only solution I can see: start the new thread executing on  
a page that I *know* is unmapped, let it page fault on the first  
instruction, and then map the page on demand.  Is this the right way  
to do it?  Am I thinking about this in the right way?

Josh