Classic Scenario multiple transaction type defined to create PO from RFX Response

Hi all,

We are using SRM 7.02 classic scenario with backend 6.06.

We transfer purcher requisition from ECC into SRM and create a RFX, from the RFX response we should be able to create a purchase order (we defined multiple transaction type for this) selecting one of them, We always get the same error Interval PO of number range object REQREQ does not exist,

Thank so much for your help

Customizing steps indicated below:

1- give internal number range for each backend document (in SRM system)

IMG: SAP Implementation Guide > SAP Supplier Relationship Management > SRM Server > Cross-Application Basic Settings > Number Ranges > SRM Server Number Ranges > Define Number Ranges for Shopping Carts and Follow-on Documents

2- Create transaction types and assign Int. Number Range

IMG: SAP Implementation Guide > SAP Supplier Relationship Management > SRM Server > Cross-Application Basic Settings > Define Transaction Types

3- we are not  using multiple backend system, even tried to give the 4  ranges (74,73,77, 75) to same backend not possible, now defined empty  :

IMG: SAP Implementation Guide > SAP Supplier Relationship Management > SRM Server > Cross-Application Basic SettingsDefine Number Ranges per Backend System for Follow-on Document

4- Give external range to the same ranges R/3 system

IMG: SAP Customizing Implementation Guide > Materials Management > Purchasing > Purchase Order

> Define Number Ranges

5- define R/3 PO external number range in the document type already used (R/3 system)

IMG: SAP Customizing Implementation Guide > Materials Management > Purchasing > Purchase Order> Define Document Types

6- give document type in R/3 system by populating BSA attibut (PPOMA_BBP trasanction) with PO document type created