Set the account number as a Qualfifier

Hi Experts!

I've configured an additional Qualifier for customer account number. My function produced the right result and the attribute mapping is successful, but the modifiers, link by this qualifier never get used.

That's my funtion:

FUNCTION GET_QP_ACCOUNT_NUMBER RETURN VARCHAR2 AS

      l_rv HZ_CUST_ACCOUNTS.ACCOUNT_NUMBER%TYPE;

      l_message applsys.fnd_log_messages.message_text%type;

      l_module  applsys.fnd_log_messages.module%type:='XX_QP_ORDER_2_CUSTOMER_PKG';

   BEGIN

      SELECT HCA.ACCOUNT_NUMBER

      INTO l_rv

      FROM hz_cust_accounts_all hca

      WHERE hca.cust_account_id=OE_ORDER_PUB.G_HDR.SOLD_TO_ORG_ID;