[TYPO3] Different tt_content.stdWrap.wrap based on colPos

[Another Vision]

Hi List
 
Sorry if this is a bit of a newbie question but I've been wrestling with
something in typo3 4.0 with the new default htmlArea RTE...
 
What I'd like is for content elements in the right or left hand columns to
have a stdWrap applied in exactly the same way that 

tt_content.stdWrap.wrap = <div class="myWrapper"> | </div> 
 
would work, and to leave content elements in the normal column unwrapped.
 
I've tried

tt_content{
  stdWrap.wrap = <div class="myWrapper"> | </div>
  if.isTrue.field = colPos
}
 
to the template TS setup, but for reasons I don't understand, that prevents
the content in the normal column from rendering at all.
 
 
 
I've looked online and found things like this
tt_content.stdWrap.outerWrap = CASE

tt_content.stdWrap.outerWrap {

    key.field = colPos

    default = TEXT

    default.value =  default|wrap

    1 = TEXT

    1.value = another|wrap



    2 = TEXT

    2.value = another|wrap



    3 = TEXT

    3.value = another|wrap

}
but so far none of the suggestions has worked very well (the above one
doesn't work and just adds TEXT in caps above the content elements) 
 
and this one 
http://lists.netfielders.de/pipermail/typo3-english/2005-August/010267.html
causes problems elsewhere.
 
I'm confused because 
 
tt_content.stdWrap.wrap = <div class="myWrapper"> | </div> 
 
offers exactly the functionality I need, and it feels like there should be a
really simple way of applying it to just certain columns... has anyone done
this before?
 
Thanks for any advice
Mike