I am doing a b-day cake in June and the customer wants a blueberry filling in her cake. Does anyone have a recipe for blueberry filling? Can I use the Strawberry filing recipe, just replace with blueberries?

You could use blueberry pie filling if you like the taste of it.

Look at this recipe and see if it may be something you'd like to use

http://www.justberryrecipes.com/ber-0038947.html

Are you using fresh berries or frozen ones? I guess you could use either with this recipe. I've made it with huckleberries, which are close to blueberries, when they are in season around here and I get rave reviews.
It's not really a recipe but whipped cream, sugar (to taste - maybe a couple of tablespoons) and then mashed berries. It makes like a mousse for a filling. You really could use any berry. I liked this recipe because it's not as sweet as some jams, the frosting seems to cover the needed sweet factor . I've made this with white cake and white buttercream and everyone asked for seconds.
Hope this helps.
Kate

Thanks everyone for your suggestions. I'm going to test run all of them. I really appreciate you taking the time to try and help. Thanks again!!