Constraining Lambda Loadings

Hi All,
I am wondering if it is possible to place constraints on lambda loadings (i.e., constraining the loadings of a two indicator construct to be equal, or constraining the average of a construct's loadings to equal 1 to set the scale by the effects coding method). I've been working primarily with the path specification approach, and I can't see an obvious way that this could be implemented, I've seen mention of equality constraints on the forums, but I can't find any mention of such constraints or suggestions in the documentation. Any insight would be greatly appreciated.