F5 pass-through ldaps request

what do you mean with:

how does that work in automap?

setting source address translation to automap means it will use the outgoing interface IP as source IP for the connection from the BIG-IP to the pool members. it won't change content or such, just source IP.

if you don't want that you will have to make sure the pool members have a route back through the BIG-IP, for example by setting their default gateway to the BIG-IP.