My specific question is in installing new plumbing under a slab.
When I pour the floor repair, I will set the drain in the slab repair. Can I also do the first sloping for the vinyl pan with this repair, spreading the concrete and mortar out to the edges?

My specific question is in installing new plumbing under a slab.
When I pour the floor repair, I will set the drain in the slab repair. Can I also do the first sloping for the vinyl pan with this repair, spreading the concrete and mortar out to the edges?

You need instructions bad! You're in trouble already if you're going to attempt to pan the shower to a sloped floor. The shower pan sets on a level floor and the mortar is sloped to a flange type shower drain,(see image).
For instructions on setting a pan for a custom tile shower base click on;
Mortar Bed Shower Floor for Tile Showers (http://johnbridge.com/mortar_bed_shower_floor.htm)
Good luck, Tom