Rest - Parameter that is optional and empty value

Hello,

We have a rest web service that we would like to test.

Let's say that this web service has a parameter called 'type'. I have the following use cases:

[1] the parameter is optional and you don't specify it :

- it must return all the entities, whatever their type value is.

- The request is looking like this : GET http://localhost/service/

[2] you specify the parameter with an empty value :

- it must return all the entities that have an empty value for type.

- The request is looking like this : GET http://localhost/service/

[3] you specify the parameter with a given value :

- it must return all the entities that have the given value for type.

- The raw request is looking like this : GET http://localhost/service/?type=theValue

As you can see, use cases [1] and [2] are different, yet the request is the same. I would like [2] to have the following request: GET http://localhost/service/?type=

Here are some things that I have read on other posts, but I havn't been able to make it work :

- I tried to set the type parameter as required, but then it is use case [1] that is not working anymore ;

- I tried to use %00 or %80 or nbsp; and tweaking with the request properties such as "Strip whitespaces", "Remove Empty Content", "Entitize Properties"

Can someone help me on this problem ?

Is there a built-in way to make it work ? Do I need to use a script ?

Thank you !