Pet store employees are usually not very good sources of information. This isn't always the case, but the worst advice I've heard has almost always come from the mouth of an ignorant pet store employee.
Your female could maternally incubate, but not in that enclosure in its current state. Glass aquariums aren't ideal for keeping balls because it's a constant battle to keep the humidity at comfortable levels for the snake. When I maternally incubated last year, my female was kept in a 40g breeder tank but she laid her eggs in a laybox lined with moistened sphagnum moss (31qt sterilite tub with a hole cut in the lid). Having the male sharing the enclosure isn't going to help, either. It's one thing to be a wild snake sharing a den in the wild where a nuisance neighbor could be driven out but in the confines of a cage, it will only cause undue stress for both snakes if he sticks around while she's brooding.
Your best bet will be to get an incubator up and running and get the eggs into it as soon as possible.
what is a breeder tank , i had a bad experiance with a incubator tonite , got it at tractor suppley 40 $ little giant , what a pos