I would imagine that it would be fairly easy to convert. I have installed a few X09 series dial locks on safes and vaults and they are fairly straight forward. You just have to follow the instructions well. Not sure how much searching you have done but if you find something you like you can ask the manufacturer if it is possible to switch out. First stop for me would be the safe companies support line. If they sell both combo and digital, it may be an easy conversion.
Not sure if this will help you but sometimes 2 cents is worth a few.
Not sure if this will help you but sometimes 2 cents is worth a few.