So when users from 10.10.10.1 access 172.24.30.10 the dmz-server sees the IP address 10.20.240.250 instead of 10.10.10.1?
Here is one way of doing it:
object network inside-10.10.10.1
host 10.10.10.1
object network dmz-172.24.30.10
host 172.24.30.10
object network NAT-10.20.240.250
host 10.20.240.250
nat (inside,dmz) source static inside-10.10.10.1 NAT-10.20.240.250 destination static dmz-172.24.30.10 dmz-172.24.30.10
That will translate all traffic destined for the DMZ server from 10.10.1.1 to 10.20.240.250
Hope this helps.