[TYPO3] Using getText format in x, y objects, how? (TypoScript question)

[Terkild]

Hello folks,

I have now spend several hours trying to find a solution for a problem 
concerning the getText (data) format.

What i am trying to do is getting an image and a couple of informations 
from a TemplaVoila FCE, and then draw the image with a box on the lower 
section of the image, the box gets its size from the submitted 
informations from the FCE.

What i am trying to do should be transparent in this code:
=====================================================
   10 = IMAGE
   10 {
     file = GIFBUILDER
     file {
       XY = [10.w],[10.h]

       10 = IMAGE
       10.file.import = uploads/tx_templavoila/
       10.file.import.current = 1
       10.file.import.listNum = 0
       10.file.width.field = field_image_w
       10.file.height.field = field_image_h

       20 = IMAGE
       20.offset = 0,[10.h]/2
       20.file = GIFBUILDER
       20.file {
         // how to get these getText values into the object
         XY = {field:field_box_w},{field:field_box_h}
         10 = BOX
         10 {
           // and here.
           dimensions = 0,0,{field:field_box_w},{field:field_box_h}
           color = #0000ff
         }
       }
     }
   }
=====================================================

I have tried with dataWrap and making a LOAD_REGISTER, but without luck,

Anyone has any suggestions what might work?

Thanks in advance!

Kind regards
Terkild