Cisco Firewall :: NAT - Multiple Ports Translated To Single Port - ASA 8.4

We are migrating from a nother brand to an ASA Cluster running 8.4.5
 
We have a web-server on an inside interface listening on a non standard port - 20111. We have created a static NAT translating the public ip to the private, so If I do http://public-ip:20111 it works. (we are using a seperate public IP for this service only).
  
Now I need to create a NAT rule that will forward requests on BOTH port 80 and 443 to the same private ip and the same port number (20111)
 
The Private address is 10.99.250.20 and the "public" (I've replaced it in this example) is 172.16.16.16 I have managed to create a NAT that will translate 443 to 20111:
 
object network 10.99.250.20 nat (Private-DMZ,Outside) static 172.16.16.16 service tcp 20111 https

But if I try to add another rule like:  nat (Private-DMZ,Outside) static 172.16.16.16 service tcp 20111 http It will simply replace the first one.
 
Is it possible to redirect both 80 and 443 from outside to the same port number and same IP on the inside?