Reporting chart component scripting

I have created “Engg. Unit” script data source to get the Engg. unit from SQL tags.

I have configured one Time series chart in report designer.

And I want to concat it (axis label + Engg. unit) with my XY chart component’s axis label field.

I am using component script to do so. but not able to access Engg. Unit data source key in script.

help…

Or also suggest way around for this.