AttributeQuery with Redirect binding

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Hi,

I'm trying to implement a SAML message exchange for (amongst others) 
attributes. For this, I want to use the Redirect-binding and the 
AttributeQuery message type. However, I can't seem to find the element 
that is used for this message type to indicate the location to which the 
response message must be returned.

For the AuthnRequest message, the element that serves this purpose is 
AssertionConsumerServiceURL. However, this is only described as part of 
the AuthnRequest message and not for the RequestAbstractType supertype 
of AttributeQuery.

Does SAML support AttributeQuery messages to be sent in a 
Redirect-binding? If so, how can you indicate the location to which the 
response must be returned in this situation? If not, is there a solution 
that is generally accepted to handle this situation?

I've thought of using the Issuer element to indicate the response 
location but the standard indicates it should identify the entity that 
*generated* the request message, which is not the entity to which the 
response should be returned in my case.

I've looked into the standard but cannot find any mention of how to 
query for attributes in a Redirect-binding. Also, I am aware that the 
redirect-binding has its constraints with regard to the size of the 
request. I would, however, like to know if it is currently supported in 
any way.

Thanks in advance,

-Jasper