After Effects CS5: impossible to import "special" .flv -Clips?

Hi,

apparently After Effects CS5 has trouble to import some kind of .flv-Clips (encoded with Sorenson Spark?).

I have a lot of these Clips, and its impossible to convert,because actually i work on some projects with CS4. Is there any way to to convince AE CS5 to import these flv.-Files? (->e.g. replace the flv.Encoder with the encoder from CS4, who has no problems and works fine....). Does anyone know the file-name of the encoder?

Or has anyone another solution?

Otherwise i couldnt use CS5 and i thrown the money down the drain...

Thanks and greetings

Wolle