According to Juice:

Altiris has announced SVS 2.1 Beta 1.5 with support for Microsoft's 32-bit Vista. This is a closed beta that is limited to enterprise customers and developer partners willing to do active testing immediately. Only a handful of applicants will be approved. Vista support will be broadly available with Beta 2 (date TBD).

Altiris Software Virtualization Solution (SVS) is a new way to use software. By placing applications and data into managed units called Virtual Software Packages (VSPs), SVS allows you to instantly activate, deactivate, or reset applications and to completely avoid conflicts between applications, without altering the base Windows installation.

Scope of SVS 2.1
SVS 2.1 adds support for MS Windows Vista and will improve support for emerging computing environments such as Dell SmartClient/Ardence, HP CCI and IBM Virtual Hosted Client/VMware VDI. A client of any type -- fat, thin, blade or virtual -- will be able to instantly "Subscribe" to SVS layers that are stored on a standard network share. User settings and data will remain persistent on the network even when the user moves to a different physical client or boots to a new baseline virtual client.

Scope of This Beta
This is not a feature complete beta. Most new features are not yet exposed and documented. SVS 2.1 Beta 1.5 includes all fixes and enhancements from Beta 1, plus additional changes to provide MS Windows Vista support (32 bit only). Virtual Software Packages created on previous versions of Windows will work correctly when imported on Vista with SVS 2.1 Beta 1.5. There are a few known issues on Vista that are documented in the Release Notes. We fully expect more issues to be identified as SVS is tested more broadly on Vista. Early customer feedback is critical to delivery of quality support on Vista when SVS 2.1 ships.

This is a closed beta. It is posted separately from SVS 2.1 Beta 1. (Beta 1 is still available as an open beta, for all customers). Customers who want to experiment with Beta 1.5 on Vista must apply on the Beta Portal and be approved by Product Management. The download includes the SVS Agent only, as the SVS NS Solution has not yet been tested with Vista clients.

Upgrade
SVS 2.1 Beta 1.5 may be installed over an existing SVS 2.0 installation. If you do this, before you upgrade, create a backup of pre-existing layers by exporting them. SVS 2.1 uses a new layer format. Existing layers will automatically be converted to the new layer format. However, there is no facility to revert layers to the 2.0 format should you need to roll back. Therefore, backing up layers prior to upgrade is very strongly recommended. Upgrades from SVS 2.1 Beta 1 do not change the layer format; however, backup is always recommended prior to upgrading (especially with beta code).

Check out the Juice article, here.