mapping of billing documents

Hi people,

I have still some problems and questions about mapping Data

from CRM to R/3.

Our scenario:

We only want use R/3 for FI and CO. Quoatations, Orders and Billing

Documents will be created only in R/3, then billing documents will be send

to FI.

So I made the following subskriptions:

All Business Partner Hierarchies (MESG)

All Business Partner Relationships (MESG)

All Business Partners (MESG)

Billing Documents (MESG)

Is it necassary to made any futher subskriptions?

Is it necassary to replicate material, service products or anything else for

the above scenario?

The BP replications works well, but billing documents are failling to replicate on R/3.

Got the this error.

The R/3 transfer status is "To be Tranfered"

The Account Transfer Status is G "Error Detected in Transfer to Accounting".

The Error Log For Billing is "Object Not Known in CO (Message Class IAOM / No.028)" and "Error in document:( Message Class RW / No. 609 )"

Also checked item category whether "ASSIGN BW/CO" is maintained.

Checked SAP notes too, but no helpful information found.

Are there any documents like the best practice guide for replicating of billing documents

available?

Thanks in advantage. Reward the maximum points for help to solve my problems.