Hi Jan,
Accurate Model Parts (AMP) (formerly U-Brass) will be releasing a set for the Special Navy (SN) Type IIA kit. This will include PE parts to correct and improve the free-flooding holes on the hull. Note that SN used the Vesikko in their design, and their kit hull holes are a hybrid of the IIA and Vesikko. There will be resin parts to replicate the ventral area, which is missing from the SN kit. There will be a few other resin parts, and a number of PE parts to improve the tower. 
Included in the AMP set will be a new corrected deck in PE brass. There will also be plenty of thin PE parts for the deck details (hatch hinges etc.) There will also be pieces for the metal sections at the bow and stern in a thinner PE. The main deck sections will have a much improved deck pattern than the SN deck. Having spent dozens of hours on this deck design alone, I can assure you there are a few major problems with the SN deck pattern. There is a problem with the metal section lengths. But more importantly they have made a significant error in regard to the slots themselves. I don't want to say publically what this problem is but once you compare the slots on an accurate design to the SN deck you will immediately see a major difference. 
Going by the info on their website, I am guessing that the Nautilus deck is very similar to the incorrect SN deck. (Note that the Nautilus Type VIIC deck was very similar to the Revell deck  and didn't correct its problems)
The AMP deck was designed with reference to four sets of deck plans - Vom Original, Beck, Sievers and Jeff Larue. The greatest priority has been on using period photos of Type IIA decks, which have been used for the design wherever possible. A great deal of care has gone into calculating the correct main slot sizes (width, length, and space between slots). 
There will be over 150 PE pieces in the set, several resin parts, flags and hopefully decals too. Included will be a 72nd scale side profile plan to help with placement of the hull PE parts. 
Due to the size of the set and the amount of time required in the design, the AMP set isn't available yet. Most of the design is done, with only some parts of the tower still to design. The decals, flags and side profile are designed. The masters for the resin parts have been built and the test casting produced. Hopefully it won't be too long before it is all completed.
Best of luck with your build. 
Cheers,
Dougie
http://amp.rokket.biz/index.shtml