Can you clarify where you would want to pass the parameter? We have discussed this internally and find 2 scenarios where this could be possible.
1) The initial data source connection, you wish to filter the JSON URL based on the dynamic parameter passed in.
2) Inside of a Windward tag IE, forEach, to return a result set based on the variable parameter passed in. IE, you wish to return a list of employees to iterate over based on the parameter you pass in.
If you can give a little more detail or an example of how you want to use this JSON service URL with Windward, it would help greatly.
The Windward Staff