SalesForce has excellent API documentation. If you are comfortable writing standard .net code you should have no trouble making a connection to SalesForce and do just about anything either on the Epicor or the SalesForce side.
The tutorial on writing a simple .net program that interacts with SalesForce will take you through all the steps needed to connect to SalesForce. You can also have SalesForce make the connection to Epicor, though I haven't gone through that exercise yet.
One of my clients has a procedure that wakes up about every 15 minutes, retrieves new quotes, turns them into Epicor orders and updates the associated salesforce quote.
Epicor also sells an addon that does some SalesForce integration.
Jim Kinneman
Encompass Solutions, Inc.