Need to transfer Custom IDocs from CRM4 to CRM7

Hi CRM Gurus,

I have requirement to transfer Sales Orders Idocs from CRM to CRM7. So we are using Standard Idocs CRMXIF_ORDER_SAVE_M2 with few custom fields. The standard IDOC CRMXIF_ORDER_SAVE_M2 has been enhanced to include custom segments and ZCRMXIF_ORDER_SAVE_M2 has been created. I have maintained the Sites and Site - Basic Type and Interface Type mapping in the source and target systems. However, the idoc when arrived in CRM 7 is not recognizing the structure and is erroring out displaying all the segments at first level.

I am new to CRM and this is a critical requirement. Please guide me. Thanks in advance for your help...!

Let me know if you require more information.

Thanks & Best Regards,

Anand Patil