Lina,
I believe the recommended approach is to leverage XPI/webMethods, which is bundled with new Tool Releases of EnterpriseOne (ie, 8.95) as the Web Services Gateway (WSG). However, I believe this webMethods license does not include the Modeler solution or the full blown version of the Integration Server, which is what you would need to create the full integration.
I think you would either need to get the full webMethods license or use WSG (which is just OneWorld and HTTP adapters running on scaled down version webMethod's Integration Server) as single point of entry into the ERP.
As indicated in the WSG guide, "Web Services Gateway (WSG) is designed only for point-to-point scenarios, where Peoplesoft EnterpriseOne must be one of the points. It is not to be used as an integration hub."
Hope this helps.
