in according with OSS Note 1802839 I developed the integration from ECC to Elster via PI 7.3 .
I execute a test with transaction FOTV, but I receive error "JCO.Server could not find server function 'FI_DE_B2A_ELSTER_XI' ".
The RFC FI_DE_ELSTER_XI (with program ID) works correctly; in Enterprise service repository the Interface
FI_DE_B2A_ELSTER_XI exists and is used.
I tried also to restart instance PI.