wsimport -wsdllocation useage (newbie)

In wsimport how do I use the -wsdllocation switch to use a local wsdl copied from a remote http site??

I am a raw newbie at web services, trying to use java se jdk7 wsimport to build a client.

My first step was a success; I simply used the remote site url?wsdl directly and wsimport built me a neat little client that worked.

Now I want to copy the wsdl over to my computer and have wsimport build my client from there, but I can't figure it out and there doesn't seem to
be any detailed examples on the web as to how to do this.

If my service's url is http://www.webservicemart.com/uszip.asmx and the locally copied wsdl is uszipwsdl.xml on my computer, what is the wsimport command line to correctly build my client?? (this is a simple service that returns the state that a given zipcode is in.)

This is just a step in my learning; the reason I want to do this is that my eventual target server is a more complicated web service
that uses https and currently gives me certificate errors when I try running wsimport on it. Another post on one of the forums said to
use a local copy of the wsdl and wsdllocation to avoid those wsimport errors.