JSONDecoder fails to decode UTF-8

I could find this bug in flex sdk 4.0.0 and also in the nightly build of 4.1.0.

Steps to reproduce:
I got a webservice that returns JSON in UTF-8 encoding. With western character sets there is no problem. But when I e.g. have Russian characters I get an exception.
I tested my service and it seems all valid. I also validated the JSON. So finally I tried a small example and it breaks as well. So I believe the bug is in the JSONDecoder.

1. put this in an application:
var d:JSONDecoder = new JSONDecoder(); //use: com.adobe.serializers.json.JSONDecoder;
d.decode("Адресная книга");
2.launch it
3.you should get an exception (at least if you have the debug version of the player)

Actual Results:
Error: Error while Parsing
at com.adobe.serializers.json::JSONDecoder/parseValue()[C:\perforceGAURAVP01\depot\flex\ide_builder\com.adobe.flexbuilder.dcrad\serializers\src\com\adobe\serializers\json\JSONDecoder.as:210]
at com.adobe.serializers.json::JSONDecoder/decode()[C:\perforceGAURAVP01\depot\flex\ide_builder\com.adobe.flexbuilder.dcrad\serializers\src\com\adobe\serializers\json\JSONDecoder.as:178]

Expected Results:

Workaround (if any):