Show dynamic label in treemap Cognos visualization

[catechacha]

Hello,
I want to customize treemap by categories in Report Studio 10.2.2. I have set:

• Dimension = total invoice amount
• Category = description of business unit (I have only one dimension)

Now when i run my report i see only:

• top left of a square: description of business unit (and this is ok)
• center of a square: the string "Total invoice amount" (this is not what i want)
• down left of a square: the string "Total invoice amount" (this is ok)

I want to show in the center of each square not the string "Total invoice amount" but the real value of the dimension total invoice amount for that business unit, for example 123456$.
How can i show this? I have tried to modify specification .json of treemap with Visualization Customizer, but i didn't have success. Can you help me? It is possible to make this change?