Add SOAP envelope in SOAP receiver

i am working on sap po 7.4.its single stack java based system.

my scenario is soap to soap. we need to send message to receiver with custom envelop.

Can you please let me know how to add below SOAP envelope in exact format mentioned below -

http://schemas.xmlsoap.org/soap/envelope/" xmlns:siiLR=" http://xyz.gob.es/ABC.xsd/" xmlns:sii=" http://xyz.gob.es/2DEF.xsd">