What version of the ASA software are you using? <= 8.2 is a lot different than >= 8.3. Ultimately your nat statements will vary with the version of the ASA software. I'm also not 100% clear what you're trying to accomplish. Ultimately you'll need 2 things with NAT with port address translation:
1) You'll need the nat statement to translate the IP / Port
2) You'll need to add an access list and assign it via the access-group command to the interface to allow the traffic from a low security interface to a high security interface.
If you can give some quick examples of exactly what you're trying to accomplish that may make it easier. The vlans aren't so much a concern as all of the 5505 interfaces are ultimately assigned to and designated in terms of vlans. Also I just ran the commands you discussed regarding creating network objects on my home asa 5505 and it worked:
object network blah-deleteme