Invoice with customer's Tax number

Hi I need to add customer tax registration to the Inoice report. Does anybody knows how to add this?

You can use this, just add this field to you Grouphead query source and you can print the rfc field with a normal string field object:

(SELECT taxreg_number from taxreg where taxreg_rel_id = cust_id AND taxreg_rel_type = 'C') as rfc

Of course the tax registration must be recorded in the customer's tax form.

Thanks malfredo32 for your reply
but it did not work for me, i am very new to OpenRPT.
Please have a look if i need to change to the below query source(Grouphead):-

SELECT

--Due Date
formatDate(determineDueDate(invchead_terms_id, invchead_invcdate)) AS due_date,

--Discount Date
formatDate(determineDiscountDate(invchead_terms_id, invchead_invcdate)) AS dis_date,

--remitto.*,
remitto_name,
formatAddr(remitto_address1, remitto_address2, remitto_address3, remitto_citystatezip, remitto_country) AS remitto_adr,
invchead_invcnumber AS invoicenumber,
formatDate(invchead_invcdate) AS f_invoicedate,
cust_number,
invchead_billto_name,
formatAddr(invchead_billto_address1, invchead_billto_address2, invchead_billto_address3, ( invchead_billto_city || ' ' || invchead_billto_state || ' ' || invchead_billto_zipcode ), invchead_billto_country) AS f_billtoaddress,
invchead_billto_phone,
invchead_shipto_name,
formatAddr(invchead_shipto_address1, invchead_shipto_address2, invchead_shipto_address3, ( invchead_shipto_city || ' ' || invchead_shipto_state || ' ' || invchead_shipto_zipcode ), invchead_shipto_country) AS f_shiptoaddress,
invchead_ordernumber AS ordernumber,
invchead_ponumber,
formatDate(invchead_orderdate) AS f_orderdate,
formatDate(invchead_shipdate) AS f_shipdate,
invchead_fob, terms_descrip, invchead_shipvia
FROM remitto, cust, invchead, terms
WHERE ( (invchead_cust_id=cust_id)
AND (invchead_terms_id=terms_id)
AND (invchead_id=<? value("invchead_id") ?>) )
ORDER BY ordernumber,
(SELECT taxreg_number from taxreg where taxreg_rel_id = cust_id AND taxreg_rel_type = 'C') as rfc;

I m trying to fill in the customer VAT number on thier invoice.I tried to put in the query but it did not work.Any ideas what format and what field lable I should use.Your help will be appreciated