Charts in NAV 2013 and higher: Datapoint hovering label in charts: How can I display different text

HansDutting

I'm currently making custom charts on custom tables in NAV 2013 R2 for rolecenters, using table 485 Business Chart Buffer.
For example a Column chart with customer vs turnover
If I use the AddColumn function the value is displayed under the column on the X-axis.
This same value is displayed in the label appearring when I hover over the column along with the turnover decimal value. (the yellow tooltip box).
If I use Customer No and Name the X-axis labels become unreadable (unless you extend the chart box).
For this purpose I want to show only the Customer.No on the X-axis, and in the textballoon the Customer No. + Name.
But I cannot figure out if that is possible in CAL or to call specific DotNet properties to influence these textballoons.
Has somebody already tried this?

If the question is unclear, I attached a picture. The orange number is what I want to be variable with CustomerNo and Name (1246 + Name) without changing the label under the column (1246).

Let me know!
Tnx
Hans D.