There is a service called "Lightscribe Direct Labelling System" that must be running in your system in order for the burning software (say Nero) to recognize that the lightscribe function is available.
Unfortunately, a lot of burning software does not ship with the lightscribe service software. Also unfortunate is that the software is oftentimes not
included in the CD that comes with the burner either.
Get the software from http://www.lightscribe.com/support/index.aspx?id=305
and install it. After that the burning software should recognize that it is dealing with a lightscribe enabled drive.