официальные рекомендации в Implementation Guide.
http://technet.navision.com/usered/A...ationGuide.htm
раздел Before you begin making modifications
http://technet.navision.com/usered/A...ifications.htm
посмотрите раздел Typical modifications
http://technet.navision.com/usered/A..._modifications
советую обратить внимание на документ
Navision Axapta Design Guidelines for cost efficient upgrades
http://technet.navision.com/usered/B...t_Upgrades.htm