layout file for theorem environment with options

[Gunnar]

Hi.
I've created an environment for examples,

{\theorembodyfont{\upshape} \newtheorem{EE}{Exempel}}

and I've managed to write an layout for it, 

# Example style definition
Style Example
  LatexType             Environment
  LatexName             EE

  Align                 Left
  AlignPossible         Left
  LabelType            Top_Environment
  LabelString    "Exempel #."
  LabelFont 
    Series              Bold
  EndFont
End


Now, the thing I want to do is to sometimes use the environment  with an 
optional argument, like  I do in this ERT:
\begin{EE}[I want this]   
   bla bla bla..
\end{EE}

to get the result

Example 5. (I want this)
bla bla bla.

The text "I want this" is written in bold, and that can easily be done without 
the [ ]-part, but I would rather use [ ].

Any ideas? I've found an option OptionalArgs but not much documentation about 
it, or how to use it.