Hi Vilnod,

First of all, fair warning, I'm a Salesforce AppExchange partner.  That being said, I've worked as an employee of SAP as a senior SD/MM consultant years ago and then ended up in senior director and enterprise architect roles at global companies that ran both SAP and Salesforce.com. Based on various successful and failed implementations, I learned a few important things along the way.  Here are a couple:

- Only replicate the minimum amount of data between systems as possible. 
Of course you need to replicate the customer master but even that should be done with thought.  The SAP customer master is structured with a basic view (Customer Number), while the sales area view allows that same customer number to have multiple sales areas, each with different attribute values.  That same customer might have multiple sales views with combinations of Sales Organization, Distribution Channel, and Division.  This is typical for large global customers.  In Salesforce that would relate to one or more customer master records called Accounts. Your sales management will expect to see data according to their sales organization, not the corporate finance department structure.  This integration requires organizational translation between Finance in the SAP ERP and Sales in the Salesforce.com CRM system because it will feed all your data warehouse and management reporting.

So that's complicated enough!  Why would you want to try to additionally keep transactional data or dynamic data such as pricing or availability synched between two systems?  It's a losing battle.  Which leads to:

- Utilize realtime web service calls between Salesforce.com and SAP to access critical data which is dynamic or involves a complex SAP module such as pricing, available to promise, credit check, etc.
If you have your master data in synch then you only need some basic SAP attributes persisted in your Salesforce.com account to enable other critical realtime transactions with SAP such as quotes or sales or service orders, including full SAP price and availability.  SGC Software has developed composite applications or "mashups" which you can set up as custom visual force pages in your Salesforce Account page layouts or other places in Salesforce screens to allow your sales teams real-time access to information in SAP that pertains to their customers.

We're actually a small niche firm.  We had started as an SAP consulting firm and got involve with Saleforce.com after migrating some clients from SAP CRM to Salesforce and then integrating back to their SAP ERP.  We're a certified Salesforce AppExchange partner but rather than the typical "anything to anything" middleware vendors, we specialize in Salesforce.com to SAP integration.  They are both highly configurable systems which often end up also being customized so we are experienced with that environment.  In any case I'll end the sales pitch and if you have any other questions, I'd be happy to share my opinions!

Regards,
Tom Ackerman
Managing Partner
SGC Software, LLC
toma@sgcsoftware.com

www.sgcsoftware.com