Hi chocho and welcome to Artist Forum!
I actually do experience the same thing too, but I don't treat it as a problem. Instead, I embrace and relish in the fact that I am not a camera and my hands are not machines designed to rigidly and prohibitively render nothing more or less than exactly an image in my mind's eye: instead, I am *artist*, so I can accentuate, accessorize, emphasize/de-emphasize, alter, adjust, redirect, CHANGE whatver I want to. Many times, as it turns out, I end up drawing something better than what I originally had in mind, as if the image in mind was merely a launching point for creativity.
Freedom in art is what keeps me going with it; where my pencil or stylus lands on a page or computer screen is my decision.
Besides...if I may get technical for a moment, what the average person "sees" in their mind's eye is a violatle, discontinguos construction of synaptic nerve firings which our artistic minds attempt to extract from to rationally render an "image".
That having been said, however, the only surefire way I know of to do strictly what you're asking is to draw from photos, life...in the end, all you're doing in attempting to draw something from the mind's eye is kinda 'tracing', right? Do it with static images until you get adroit at that then adapt the skill set to drawing from your imagination.