Parameter label in Z transaction

Hi abapers,

I'm stuck.

I created transaction ZFKKINVDOC_SIM_DEL as copy of FKKINVDOC_SIM_DEL - Simulated Invoicing Documents in transaction SE93.

In layout (attached picture) I added new fileds %_PDELDAT2_%_APP_%-TEXT and PDELDAT2 which will be populated with Date_from parameter value.

In corresponding program ZRFKKINV_DELETE_SIM_INVDOCS I included that additional parameter:

PARAMETERS: p_period    TYPE retper_del_kk,
                       p_deldat    TYPE rsdeltodate,
                       pdeldat2    TYPE zrsdelfromdate.

Data element zrsdelfromdate is defined with corresponding field labels "Delete from Date"

Problem is that value of layout element %_PDELDAT2_%_APP_%-TEXT doesn't pick data element zrsdelfromdate  field label. Instead parameter pdeldat2 name is displayed.

What's missing here?

Thanks in advance,

Mario