Anyway, by adding SOAP does not give anything immediately, but indirectly it opens up the door for writing applications which work seamless across firewalls, since it will be based on HTTP port 80.

Which it is kind of hard to imagine many people needing very often, given the nature of the device we are talking about.

I think, Mozilla supports SOAP

It would appear so, yes:

http://lxr.mozilla.org/mozilla1.0/source/extensions/xmlextras/docs/Soap_Scripts_in_Mozilla.html