I thought it would be easiest to ask the guys behind the submission address (submissions@synesthesiarecordings.com).
Not that i got a real answer.
If you have an idea how to follow up, I'm interested.

Andras

---------- Forwarded message ----------
From: Federico Placidi <federico.placidi@gmail.com>
Date: 2012/1/3
Subject: Re: Sonic Screens - why no pd/sc?
To: András Murányi <muranyia@gmail.com>

Many thanks for your interest in our call,

About PD and SC there is no specific reason,

It is just an internal policy.

Many thanks,

Federico Placidi, Matteo Milani

2012/1/3 András Murányi <muranyia@gmail.com>

Hello,

I'd like to know why PureData and SuperCollider based projects are excluded from the contest.

Thanks,