The Special Edition and Special Edition PLUS sound sets have been updated: http://vsl.co.at/en/68/375/460/295.htm
Most of the problems described come from a SoundID mismatch between what the staff is requesting and what the sound set is sending.
If you have string sections included in your score, proceed as follows:
Open the Sibelius Mixer and set the SoundID (third line) of your string sections to the same name as in Manual Sound Sets (e.g. strings.vioin.ensemble.14 players). Also set the channel numbers.
There is still a bug in Sibelius 5.2 which can not be corrected with a sound set, but hopefully will be in the next Sibelius update.
Here is one more information which I got directly from Sibelius
"Also, there’s a bug in Sibelius that it doesn’t realise articulations have been put in the score and either plays the wrong patch or nothing at all. To force Sibelius to see the articulation changed you have made you need to put in a slur. Weird, but it works. We are looking into better ways of fixing this in due course."
I recommend users with Sibelius 5.1 to stay with this version until the next update.
Best,
Andi
Btw. We have a new sound set for our Harps online.