Web Service requirements are specified in documents.
Can I use Delphi 2010 and this web service or Can I create a dll with any other native language?
See:
http://www.oasis-open.org/committees/wss/charter.php
http://en.wikipedia.org/wiki/WS-Security
You can try Apache Axis2/C, an open source project, released under the Apache 2.0 License.
Apache Axis2/C is a Web services engine implemented in the C programming language.
It is based on the extensible and flexible Axis2 architecture (for the Java platform).
The following WS-* specifications are supported, either as built in modules or as separate Apache projects:
- WS-Addressing - Built in to Axis2/C
- WS-Policy - Built in to Axis2/C
- WS-Security - Implemented by Apache Rampart/C project
- WS-SecurityPolicy - Built in to Axis2/C
- WS-ReliableMessaging - Implemented by Apache Sandesha2/C project
- WS-Eventing - Implemented by Apache Savan/C project
I have not studied it in detail, but in my experience most Apache projects are among the best open source projects, well documented and widely used in (non-commercial and commercial) applications.
Update: Support for WS-Trust is mentioned on the Apache Rampart/C pages.