Note that SOAP API is deprecated in favor of REST one.
If you are working on new development I will strongly suggest going with REST API
Just in case here are few links that might help with SOAP issue:
vSphere Documentation Center
The value property represents either the input or output parameter value for this particular workflow token, in the form of a string.
f the type is an array of objects, the value is a string of the following format:
"#{#<type1>#<value1>#;#<type2>#<value2>#...}#"
Re: VMware Orchestrator WebService and Perl