IPN responses cached

[FST88]

I'm trying send differents customs var in my request (sandbox), but the IPN always responds the same.

I need should delete all paypal cookies to work OK.

this is part of my send form

<input name="rm" type="hidden" value="1">
<input type="hidden" name="cmd" value="_s-xclick">
<input type="hidden" name="hosted_button_id" value="XXXXXXXX">
<input type="hidden" name="notify_url" value="XXXXXXXXXXXXXXXXXXXXXXXXXXXX">	
<input type="hidden" name="custom" value="nombre=Juan&amp;apellido=Perez&amp;email=xxxxxxxxxxx&amp;pais=Alemania">

But my IPN response is old. it seems that the answer is cached

This is the request 

This is one of the requests that I send to paypal

The notification url is fine and a custom is also fine. But the Paypal answer is an old information, so that it works OK, I have to delete paypal cookies.

Has Paypal any technical assistance service?

thx.