Where can I check the value of field BLGCHR

Hi experts,

I am trying to modify customer exit EXIT_SAPLF048_001. I have an active project and active component with the following code in the Z include:

BREAK-POINT.

I_RELATION-BLGCHR = F180A_BLGCHR_EXIT2.

MODIFY RELATION_TAB FROM I_RELATION INDEX 1.

When I run transaction FB70 I am stopped at the breakpoint and I see I_RELATION-BLGCHR populated as expected. However when the document is posted I do not see anything in the reference field when I look at it through FB03. Additionally, when I check table RF048 I see that there are zero entries.

Where can I see the changes in BLGCHR? How do I know the customer exit is having any effect?

Thank you