Any way to force always 60Hz in a PAL-DC?

I know that I can patch isos to make them run at 60hz in my PAL Dreamcast, but I want to use my original ones that play at 50hz (like KOF99 Evolution). I know that there's a way to modify NTSC Dreamcasts to run at 50Hz for playing Resident Evil Code Veronica, I want the opposite modify in a PAL DC, if possible.

Also, to run japanese games I use a (copied) gameshark, and I think that surely I can put with it a "cheat" that forces the game to be always at 60hz, but this gameshark doesn't feature cheat searching, so, anyone knows one to use? Because on the internet there is not any cheat for it (logic because the gameshark was not released in Europe, by the way).
with the gameshark, when I select "start game without codes" my dreamcast resets and put itself into 60Hz mode, because of the logotype is orange instead of blue and the image is at 60hz. Great, but when the game starts, it not only puts itself into 50hz mode, the image is not centered vertically at all, being a black border on the top and loosing image on the bottom.

So, the gamesharks' only useful to see the BIOS at 60hz... and that it's not really useful .... :
there's no way other than buying a NTSC DC. the dc-x can force some games to use 60 hz, but not all.

the mod for NTSC dcs is NOT for playing in 50 hz, in only fixes the picture being shifted off-center as you experienced with the gameshark.

btw, the gameshark was released in europe too, but under the name Action Replay.
Well, but I think that, without having to buy a NSTC-DC, I can play original games at 60hz, using the gameshark and activating a "cheat" that forces 60hz, like patches do in isos... but without cheat searching feature, I can't know the code... any idea of how to get it? any person who can get it?
for some games, you'd have to enter hundreds of codes, since some games set the 50 Hz video mode every single time you change the screen, level, etc.
I think that these games put the 50hz mode always the same way, so one single patch will affect all them. My Street Fighter double impact copy was patched the same way for all the 50hz protections I found and it worked without prob, the same thing as a gameshark cheat could work, I think.