Enterprise service for vendor creation/modification

Hi All, We are actually having scenario, once the vendor is created/modified in ECC then the information should be sent to third party. Third party will create a vendor with new vendor number at their end and will share the new vendor number with us to update the standard table with third party vendor number corresponding to ECC vendor number. We have thought to implement this using IDOC-> SOAP-> Proxy using PI as middleware. 1> ECC will send the vendor data to third party using IDOC via PI 2> Third party will receive the data using SOAP from PI and will send the additional vendor number in response. 3> PI will send back the response/additional information to ECC using custom proxy. In the above scenario we are planning for custom proxy to receive the response at ECC end. So we are looking for a solution which can be better and more standard. Or we wish if we get a synchronous enterprise service for this scenario? Thanks, Binod