Wondering if anyone has experience with Sharepoint developing and WCF services because I'm having a hard time with this one

We have a client application that connects to a sharepoint server and it needs to retrieve some data from that server (We also have an application server-side to do that work). The data is quite big and it take a lot of time to prepare it before sending it to the client so we want to use WCF service in order to stream that data from the server to the client. This part is quite simple as it is only a "Request/Response" WCF service.

The problem I have is the fact that preparing the data on the server takes some time. We want to be able to inform the client about the different stages (progress) we are going through before sending the data. In order to do that I though I could use a duplex wcf service (Callbacks) in order to let the client know what the server is currently doing, but it seems that Sharepoint cannot host Duplex WCF services.

If anyone has any idea on how I could achieve that pls let me know. Any help would be greatly appreciated.

I'll let you know if I find something in the mean time.

Thanks