FireMonkey is a new cross platform component library for Delphi. It has lots of similarities to VCL but is designed to supports several targets including WIN32, WIN64, OSX and iOS. Localization of a FireMonkey application is similar to localization of a VCL application. You add the original WIN32 application (.exe) or library (.dll) file into a Sisulizer project. Sisulizer scans the resources of the file and finally creates localized files or localzied resource files.
The biggest different between VCL and FireMoney localization is that compared to VCL you can have multiple target files. FireMonkey can have several target files: WIN32, WIN64, OSX, etc. When you create a project you only have to add one target file into Sisulizer project. Most often this is 32-bit Windows target but it can also be 64-bit Windows target. All other targets are added as platform files. Platform file is a file that Sisulizer handles like the main file (e.g the one you have added in to the project). Using this approach we eliminates the same resource items appearing multiple times. Starting from Delphi XE2 also VCL can have two target files. One for WIN32 and another for WIN64.
Delphi does not have a good localization support for FireMonkey. The platform itself is very much localization ready but Delphi IDE does not have any way to create the resource files for your application. Instead FireMonkey contains TLang component that provides very rudimentary localizartion support. It requires that you add TLang component on every form and manully maintain the translations of each forms. This is very time using and frustrating. You should not use TLang and you don't have to use it if you use Sisulizer. If you already have a project using TLang you don't loose any translation you have allready done. Just create a new Sisulizer project containing your application. Sisulizer automatically imports translations from each TLang component. Once imported you can safely remove TLang components. You won't need them any more.
Sisulizer's FireMonkey\Converter directory contains a sample that shows how to localize a FireMonkey application with multiple targets.