SOAP call using proxy

Hi experts,

  I'm struggling to get a SOAP call out from JS. The whole payload, url and everything seems to be fine : doublechecked with SOAPUI and works fine. The only difference in this case is that I have to use proxy settings in SOAPUI to get the message out successfully. Anyway, it works... But not with sm. Obviously I set up some parameters in sm.ini:

JVMOption1:-Djava.net.useSystemProxies

#JVMOption1:-Dhttp.proxyHost=httpproxy.QWE123-intranet.de
#JVMOption2:-Dhttp.proxyPort=8080
#JVMOption3:-Dhttp.nonProxyHosts="*.kakukk.hu"
#JVMOption4:-Djsse.enableSNIExtension=false

As you see I've been trying different setups but the result is the very same :

Script <unknown script> line 0: ERROR uncaught exception: Error calling method: doSoapRequest in class: com/hp/ov/sm/server/utility/SoapClient Exception (com.
sun.xml.messaging.saaj.SOAPExceptionImpl: com.sun.xml.messaging.saaj.SOAPExceptionImpl: Message send failed) at char 1
Error calling method: doSoapRequest in class: com/hp/ov/sm/server/utility/SoapClient Exception (com.sun.xml.messaging.saaj.SOAPExceptionImpl: com.sun.xml.message

Which is totally uninformative btw but we're actually used to that with SM

Long story short: 

Why wouldn't my very same call succeed from SOAPUI but not from SM with the very same proxy settings?

Thanks in advance!

BR,

Dávid