GET and POST redirect/proxy via htaccess

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server

Hi,
there is a website that asks with ajax for some web-service web-methods. I don't have its code.
It sends POST requests and expect to get JSON as an answer.

I write this web-service. I use hataccess file with many rewrite rules.
Some rules redirect client request directly or through proxy.

Thus some stays POST requests, like the ones that pass through
RewriteCond %{HTTP_REFERER} ^http://(.*)/Bing$ [NC]
RewriteRule /ActivitiesService.asmx/GetLatest$ http://%1/ActivitiesService.asmx/GetLatestSearchActivities [NC,L,P]

And some I rewrite t a queryString form:
RewriteCond %{HTTP_REFERER} ^http://(.*)/([0-9]+) [NC]
RewriteRule /ActivitiesService.asmx/GetLatest$ http://%1/ActivitiesService.asmx/GetLatestByActivityType?activityType=%2&type=1&timestamp=10000 [NC,L,R=301]

I did so because I didn't find a way to dynamically add an additional parameter to the method.
I couldn't leave it in POST method.

The methods that are called with querySring were added
[ScriptMethod(UseHttpGet = true)]

the thing is that when I [R] redirect instead of
proxy some data is lost:

Content-Type: application/json; charset=UTF-8 turns to something with 'xml').

Even when I use Fiddler requestBuilder with this data
i get JSON as a response but with an error inside it.

I tried to call one method from another which doesn't have
ScriptMethod(UseHttpGet = true)] and is redirected by

- and everthing worked fine. Got good JSON object as expected.

Someone has an idea how can I modify my htaccess file or web-service API attributes?
<code>
[CODE]
RewriteRule ^/Bing$ http://%{HTTP:Host} [NC,L,P]
RewriteRule ^/Zynga$ http://%{HTTP:Host} [NC,L,P]
RewriteRule ^/([0-9]+)$ http://%{HTTP:Host} [NC,L,P]
RewriteRule ^/CT([0-9]+)$ http://%{HTTP:Host} [NC,L,P]

RewriteCond %{HTTP_REFERER} ^http://(.*)/Bing$ [NC]
RewriteRule /ActivitiesService.asmx/GetLatest$ http://%1/ActivitiesService.asmx/GetLatestSearchActivities [NC,L,P]

RewriteCond %{HTTP_REFERER} ^http://(.*)/Bing$ [NC]
RewriteRule /images/ConduitLive_header.png$ http://%1/images/Header_WatchItBing.png [NC,L,R=301]

RewriteCond %{HTTP_REFERER} ^http://(.*)/Zynga$ [NC]
RewriteRule /ActivitiesService.asmx/GetLatest$ http://%1/ActivitiesService.asmx/GetLatestZyngaActivities [NC,L,P]

RewriteCond %{HTTP_REFERER} ^http://(.*)/([0-9]+) [NC]
RewriteRule /ActivitiesService.asmx/GetLatest$ http://%1/ActivitiesService.asmx/GetLatestByActivityType?activityType=%2&type=1&timestamp=10000 [NC,L,R=301]

RewriteCond %{HTTP_REFERER} ^http://(.*)/CT([0-9]+) [NC]
RewriteRule /ActivitiesService.asmx/GetLatest$ http://%1/ActivitiesService.asmx/GetLatestByCtid?ctid=CT%2&type=1&timestamp=10000 [NC,L,R=301]
[/CODE]


Thanks for any help !
Have a great weekend