System::Variant::OlePropertySet is a wrapper for calling Exec. You can use System::Variant::OlePropertySet to set the value of a property on an interface that is the System::Variant::Variant object's value. 

name is the name of the property whose value is set. Note that this parameter's value may be different for localized versions of the Automation server. As a result, it is a good idea to use a string resource for this value if the application is intended for multiple locales. 

args is a TAutoArgsBase object that contains the parameter values of the property's write access method. Typically, this is an instance of TAutoArgs with one parameter (the value to set).  

As an alternate syntax, there is a templatized version that can be called with up to 10 arguments, where the template parameters specify the types of each argument.

System::Variant::Exec 

System::Variant::OlePropertyGet