how to use an intrepid package in hardy? whit out move to intrepid?

[David Faerman]

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hi
i need use asterisk 1.4.21 which is in intrepid but my system is hardy...
there is 1.4.17 for hardy but it is a bit old...
i tried to change the control file (debian/control) in the 1.4.21 whit
the control file from 1.4.17 but it didn't work
what can i do?
thanks
David
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