See table-1 brake down of user lisences, if 5505 has 10 user any more outbound internet connection exceeding 10 will not occur.
Best is to obtain Security Plus license ASA5505-SEC-BUN-K9 to not have any restrictions and use all features such as DMZ support etc..
http://www.cisco.com/en/US/prod/collateral/vpndevc/ps6032/ps6094/ps6120/prod_brochure0900aecd80402e36.html
quote from link for 10 user license
In routed mode, hosts on the inside (Business and Home VLANs) count towards the limit only when they communicate with the outside (Internet VLAN). Internet hosts are not counted towards the limit. Hosts that initiate traffic between Business and Home are also not counted towards the limit. The interface associated with the default route is considered to be the Internet interface. If there is no default route, hosts on all interfaces are counted toward the limit. In transparent mode, the interface with the lowest number of hosts is counted towards the host limit. See the show local-host command to view the host limits.
http://www.cisco.com/en/US/docs/security/asa/asa80/asdm60/user/guide/specs.html#wpxref1178025
HTH
Rgds
Jorge
Jorge Rodriguez
