>>An error was discovered processing the <wsse:Security> header.
>>We have tried it with classic PowerBuilder 12.5 and 12.6.
The web service client generated by PowerBuilder Classic is not capable of supporting WS-Security.
The WCF client in PowerBuilder.Net can. There are ways you can use a client generated by PowerBuilder.Net in PowerBuilder Classic. Or you might create your own local web service that interacts with the remote one and is configured so Classic can call it.