How to debug in VS instead of JIT Debugger?

UPDATE: go to the process through the menu: DEBUG / Attach Process / iexplore.exeshows "Automatically: Silverlight Code". that is, VS 2010 already attached to the process. Why is it not suitable for debugging?

I have an unpleasant debugging behavior on my laptop that I would like to fix. I accompanied the demo version of Silverlight TV 46: What is wrong with my WCF service ?

On my computer, I noticed that starting a new one ArithmeticException()in the RIA service causes the debugger to get involved on time (the bad thing - I want VS). I can put a breakpoint on the line throw new ArithmeticExpression(), and VS stops as usual. Press F10 and I still get the debugger right on time.

On the Yvor computer (leading to link Ch 8 above), the visual studio debugger starts, not just on time. What am I doing wrong? Perhaps the Reddate Reflector was previously installed (now it's gone).

ERROR: Visual Studio Just-In-Time Debugger Code: 4004 Category: ManagedRuntimeError Message: System.Reflection.TargetInvocationException: An exception occurred during the operation, which invalidated the result.

Verify...

Possible debuggers:

New instance of MS VS 2010, 
New instance of VS 2008.  

• [checked] Set the currently selected debugger as the default value.

• [unchecked] Manually select debugging mechanisms

• Action: Hit Yes.

2nd ERROR:

Unable to connect to the failure process. The debugger is already attached.

I spent several hours finding a way to solve this problem.

The browser is IE9 / Silverlight 4.