What also might help is STM32CubeMx, which you can download from ST.
This will show alternative functions and you can define all pin assignments and more. Even if you do not use HAL, the generated code will give you clues about how the initialization can be done for your setup.
I don't have a STMF105 myself (neither used FSMC), but you can in STM32CubeMX define probably all pin positions. On the left (green/black items) there is probably FMSC where you can enable it and edit settings, than in the menu 'Configuration' on the top there are more settings possibly. Than you have to generate code, in that code, you can see the initialization code generated for FSMC. Follow the initialization code for FSMC to see what CubeMX made out of it, and convert it (manually) to the IDE you use.