Hi Erik,
today I found out a "workaround" for this error.
As our ESB had some problem with the "Id" attribute that is generated into the <Assertion>-tag by soapUI Pro,
we decided to insert it manually.
So our assertion looks like this (please have a look at the line starting with "wsu:Id"):
<Assertion
...some namespace-declarations...
xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd"
wsu:Id="abc123"
MajorVersion="1"
MinorVersion="1">
</Assertion>
And as a big suprise... now everything works fine. The "MajorVersion" attribute keeps its value.
Obviously soapUI has a problem when it must add the "Id" attribute.
But when this attribute is already defined, the values are all kept (not changed).
By the way, is there a way to tell soapUI to use a certain attribute as "Id" (e.g. "AssertionID")?
Maybe this helps you to find/solve the problem.
Best regards