Passing Captivate Variable to Flash AS3

I know I have achieved this before but for the life of me I can't recall how I did it. I have a variable in CP which is a simple maths function adding up a series of user numeric entries. I need to change the position of a object on the CP stage based on this numeric value but couldn't find a way of using the maths output as a usable variable so assumed I could call it into Flash and do something that way. Now....how do I read a custom User Variable into Flash?

Any ideas or direction would be greatly appreciated...

Mike