Thanks for your test, you gave me an idea, I'm progressing.
I'm in an enterprise network and use a proxy to connect soap sites. My problem occurs when SoapUI orders the proxy to connect an SLL soap server. The CONNECT request does not have the defined User-Agent (and that's my problem), maybe the soap requests inside the SSL tunnel will have it but i can't tell.
I'm looking for a work-around, but I'm not optimistic.
In your case,it sounds to be an issue with the environment you test! I could not even able to reproduce this issue in SoapUI Pro 5.2 in an enterprise network. As a work around, I would suggest you to manually edit the request passed by SoapUI through some web debugger tools like Fiddler, HTTP Watch, Burp Suite etc.,
Here are outputs when I use an http site trough a proxy :
wireshark dump :
Now traces for httpS request (I only add an 's' in the url, same request) :
Wireshark dump :
As you can see, SoapUI does not add my user-agent in this case. I don't know if it is the attended behaviour for soap developpers, but it is problematic for my company, we can't use SoapUi in our environment 😞
I made a lot of tests, and it appears the problem is only with the CONNECT method used to reach https sites trough proxies. Get or Post have the correct user-agent set. I find a work-around by using fiddler and fixing my user-agent in it.