Interface or func mod not found in WE19 while Debugging

Hi Friends,

I am working on Inbound IDOC.

Customed IDOC type. Creaed a Z inbound function module,

Z Message type

When i went to WE19 and given IDOC number and selected Inbound func module in F4 help.

Then i am getting an Error

Interface or function module <func mod name> is not found

can any one correct me what is wrong going on

when i am giving other Inbound function module in WE19

the control is going for Debugging.

Am I making any mistake while creating the Inbound func module ?

Import Parameter:

IM_INPUT_METHOD like BDWFAP_PAR-INPUTMETHD

IM_MASS_PROCESSING like BDWFAP_PAR-MASS_PROC

Export Parameter:

WORKFLOW_RESULT like BDWF_PARAM-RESULT

APPLICATION_VARIABLE like BDWF_PARAM-APPL_VAR

IN_UPDATE_TASK like BDWFAP_PAR-UPDATETASK

CALL_TRANSACTION_DONE like

BDWFAP_PAR-CALLTRANS

Table:

T_IDOC_CONTRL like EDIDC

T_IDOC_DATA like EDIDD

T_IDOC_STATUS like BDIDOCSTAT

T_RETURN_VARIABLES like BDWFRETVAR

T_SERIALIZATION_INFO like BDI_SER

Kindly Guide me if any things to be done

while creating an Inbound function module

Thanks in Advance

Ganesh