ssas - MDX IIF evaluation of string value -

Another MDX question;

As told in this question

I have a value of type string which holds 4 digit numbers. I want to evaluate the first number or character of that string

So I do this:

  IIF (([Kostensoort]. [Costan code] & gt; [Cochtenosort]. [Costan Code] 8, 000), [Measures]. [Incom Bedrag] + [Measures] [Bank Bedrag], [Measure]. [Incon Bedrag]]   
 Syntax: IIF (Evalutation, Correct expression, false expression)  
 What really happens is that in any way I try to write an expression, Slia evaluates wrong. I know this because the price is printed. If I enter a constant number, which is also printed in my cube.  
 Yes, I know that specifying the values ​​of the Costan code as an integer, even though its string, I tried to use the installer and the left, resulting in no results Happened.  
 I'm sorry about a loss here, what to do. Welcome to any insights   
 
 
 You need to make sure that you hold the current member of your dimension Your example is probably returning "all"  
  [kostensoort]. [Kosten code]. Current Message   
 Once you can change which you can use.  
  IIF ([Costanosart]. [Costan Code]. Current Member)> = 7000 and [Costensource]. [Costen Code] 8000 rupees), [Measures]. [Incap bedrag] + [solution] [bank bedrag], [remedy]. [Inslote bedrag])