Look at any of the following Wcf bindings:
Assume only signatures are used (no encryption):
Then a soap request would look like this:
Note that a pem formatted certificate needs to be used. Wcf likes pfx formats more, so check out the instructions here on how to do the conversion.
You should also be aware that Wcf.js by default does no validate incoming signatures from the server. If you wish to validate them check out the sample here.