You know the argument: SaaS applications are great for green field deployments, but difficult or risky to integrate with those legacy applications where all the really important data lives.

With its announcement of ApexConnect, an integration tool to connect on-demand applications to back-end systems, analysts claim Salesforce.com has moved to stuff that bogeyman back in the closet and has given SaaS enterprise-level capabilities.

The company said its ApexConnect integration services would be built on Salesforce's Apex programming language for multitenant applications announced last month. The new tool would allow about 400 third-party applications on the company's AppExchange platform to work with legacy applications, Web services, and other on-demand applications.

Apex uses a syntax that most Java programmers will find familiar and allows any component or application created in it to be shared with any other application on the AppExchange.

The new tools include ConnectOut, an outbound messaging API that could orchestrate an event in an external system, such as SAP, based on a trigger event in Saleforce.com, senior vice-president of marketing at Salesforce, Kendall Collins, said.

"It has the ability to kick off a process with an SAP or Oracle system," Collins said.

Another ApexConnect tool, ConnectOracle, would give IT the capability to connect to any Oracle back office system to synchronise data between Salesforce's CRM application and Oracle's ERP systems, he said.

For example, a new account in Salesforce could be automatically added to Oracle's billing system or enable a business process such as sending out invoices or delivery notices or matching a new order against a previous discount schedule stored in a contract management system.

The Apex API will also allow middleware partners including Tibco, Informatica, Web Methods, IBM and Oracle, to connect to any part of Salesforce's on- demand system.

Taken together, Salesforce's SaaS platform, AppExchange partners, and ApexConnect showed SaaS encroaching on enterprise capabilities and reaching a critical mass that would allow IT to build end-to-end system processes, principal at Beagle Research, Denis Pombriant, said.

"One of the main themes that runs through the history of IT is vendors and companies trying to figure out how to support business processes the way they want to run them from the very beginning to the very end," Pombriant said. "This is the end game."

The Apex programming language will be available in the first half of 2007 according to Salesforce officials.

"[Systems integrators] have been holding back, [on SaaS] waiting to see what the next big technology shift is going to be. Announcements like this that will help them decide," Pombriant said.