According to that shAstra, Shiva and Shakti together form the paraBrahman. All the universe is a reflection of that paraBrahman. By saying this it does not mean that the reflection is outside of Brahman. Nor does it think of a ‘kevala-shivam’ ( ShivaM and ShivaM alone) that has no connection with the universe.
Since the paraBrahman, according to this school, is shiva as well as Shakti, the reflection (AbhAsa) is due to the presence of Shakti. And even then, it is not like light and its reflection, wherein we think of the reflection outside of the light. # There can be nothing outside of Shakti. Siva-Shakti is one. Within that one there comes an internal spandanaM and the duality is presented. Again the presentation is not outside of Brahman. Just as a reflection shows itself in the mirror, there is nothing outside of the mirror.