After sending a copy of the email petition from here, I got a response from Kathrein.

They say they will not publish the sourcecode on their website, only by CD and for a cost of 15 euro plus VAT and shipping. Additionally, the only sourcecode available is that mentioned on their website. (so not possible to have a diseqc 1.2 modification)

Additionally, they say they have no plans for diseqc 1.2 in the future.