Hello Quentin,
I'm not sure what do you mean by "Win64 services", but you can try to enable the
"64-bit Component" flag (from "Organization" page) for your service component and see if this helps.
Our "Services" page uses the predefined Windows Installer
"ServiceInstall" table which installs services by calling the
"CreateService function". The "ServiceInstall" table allows only the following service types:
1. A Microsoft Win32 service that runs its own process.
2. A Win32 service that shares a process.
3. Win32 service that interacts with the desktop.
Let us know if this helped, otherwise please give us more details about your service installation requirements (maybe you can tell us how do you manually - outside of Advanced Installer - install it on a 64-bit machine).
All the best,
Daniel