Damn this "shell" sucks, in so many ways. Anyway:
wget.exe --post-file=./input.xml --header="Content-Type: text/xml; charset=utf-8" --header="SOAPAction: ""http://opcfoundation.org/webservices/XMLDA/1.0/Write""" -O output.xml http://localhost/OPCSimaticNET/sopcweb.asmx
QotD comes from Earl McGraw, Texas Ranger:
"Well, it's been one long goddamn hot miserable shit-ass fuckin' day every inch of the way."