The save file looks to be the exact same as all the other Assassin's Creeds (has a GAME1A & GAME1B), and modding the money value I assume works the same way. However I tried it and it did not stick. I may have modded the wrong one; it's late and I'm sleepy, so I'll have to make more money to change the value to narrow it down.
Save attached with 2120 money.
I used this old thread that had the tutorial:
I deleted GAME1B; just modded GAME1A, but no effect. Maybe someone can have a look at it, and perhaps make a Save Editor to save us all the trouble, and perhaps look at other things to mod like number of crafting items.