You can try with XQuery. In the property transfer step select Use XQuery checkbox as you see in the image below. And use this code:
declare namespace soap='http://schemas.xmlsoap.org/soap/envelope/';
declare namespace ns1='http://ws.example.com/roma/201907';
<ns1:offer>
{
for $id in //*[local-name()='hpKeycode'] return string($id)
}
</ns1:offer>
EDIT:
If you want to avoid the use of XQuery, you can add three Transfers on your property transfer, on each one use:
First id
(//*[local-name()='hpKeycode'])[1]
Second id
(//*[local-name()='hpKeycode'])[2]
Third id
(//*[local-name()='hpKeycode'])[3]
Hope this helps,