Microsoft’s Silverlight 4, which is an upgrade to the company’s rich Internet browser plug-in platform, is set for release on Thursday, according to Microsoft representatives.

Although the subject of a presentation Tuesday at the Visual Studio 2010 launch event in Las Vegas, the technology will not be available until two days afterward.

A Microsoft official on Monday stressed “line of business” capabilities in Silverlight 4, including printing and control capabilities, with controls offered for functions like charting.

“A lot of the corporate accounts that we work with, a lot of the ISVs that we work with, they’ve been waiting for this functionality,” said Eddie Amos, Microsoft general manager for developer platform and tools product management and marketing.

Version 4 also offers more refined capabilities for running Silverlight applications outside of a browser. It provides XAP signing and verification for application integrity as well as custom window chrome for application presentation flexibility, Microsoft said.

Also featured in Silverlight 4 is support for the Google Chrome browser.

The April 15 rollout will feature the Silverlight runtime and a plug-in for Visual Studio. Silverlight 4 will be available at Microsoft’s website.

Silverlight also is being leveraged for development of applications for the upcoming Windows Phone 7 platform.