Software Deployment

The above works fine manually but not through CA.Do you mean it doesn't work at all or just not silently?

If your CA is in the Deferred sequence (as it should be), you can't use [WindowsVolume] or any but a very restricted number of properties. You need to use the special CustomActionData property. Its use has been documented here ad nauseum so I won't repeat it.

For the various DPInst command line switches (which you may need to suppress certain dialogs), refer to this page http://msdn.microsoft.com/en-us/library/ms790806.aspx

I don't use DPinst myself, but I'd check you don't need to use quotes around that path to the inf file as it contains spaces....