< SNIP >
>2. The parameters problem is a COM thing. I don't have a solution but the only time the parameters must be completely stated is if I instantiate the class using the CREATEOBJECTEX() function or call the web service. Any other method is not sensitive to the optional parameters.
< ENDSNIP >

I'm posting this for future searchs on this topic.

Bob Archer was right, I found the following in the SOAP Toolkit help file:

"Optional parameters are not supported in interfaces mapped to SOAP. Values must be provided for all defined parameters."

Still doesn't explain why all parameters must be passed when using CREATEOBJECTEX and _COMATTRIB for the method is set to one required parameter.