I'm using/testing this Plus version: 188.8.131.52
1) YOU CAN IMPORT your old sound pack (plp file)
Go to the "Sound Library" (button available only in the classic menu)
The process is almost the same as in MSN, except...
2) Except after importing you HAVE TO EDIT them, one by one [evil laugh
], pressing the button "UPDATE SERVER" - otherwise your contact will not listen the sound ^^
(I see this as a bug, once the software could do that automatically - just like in the MSN: update server when you try to send the sound...)