If/where there is a will, there is a way  

(do you have this or a similar proverb in Turkish? or how would you translate this?)

I came across this expression once: "Azimle yüce daðlar çevirilir" (With determination high mountains will be flipped), which I think comes pretty close. I think that´s the kind of question that would be best answered by a native speaker though

I cannot really think of any idiomatic expression which would have exactly the same meaning.

It might be translated in this way but it won´t be a mot-a-mot translation:

"Azmini yitirmezsen muhakkak bir çözüm yolu bulursun." which would rather mean

"If you don´t let go of your will/determination, you will certainly find a solution."

there is another common and funny idiomatic expression but it is pretty informal:

"Azimle sýçan betonu deler." which means

"If you have a shit with enough determination, you can even bore through solid concrete."

I think other native speakers may give me a hand, because I beleive something closer and idiomatic can be actually found. 

Thank you both, really. I think both translations could actually work well, especially the ´mountain´ one. But I like the informal ´shit´ one too. It´s really funny.