you mean the outer door?
you need to make a new script for it..
currently, it only works on the vault 13 map... , since it has to interact with the entry computer which uses a M_VAR..
to make it so you can "use" it like a normal door ( ie run up to it, fiddle with it, and it opens.. ) you have to edit it's prototype...
see the link in my signature for my website which has a tutorial on editing prototypes... as well as many othe usefull tutorials...
you need to set it's action flags to make it useable... ( click "action flags" button and answer "yes" to "useable?" )