Hello EleBriscoe,
This is a hard thing to workaround, and is an old issue.
After a patch, Ashley did a code behavior where depending on the slope angle, the player could drop or stand in.
And wanting slip over the surface I did a detector anchored to the player, where it detect the slopes angles by overlapping it (by the adjacent side of the triangle formed between the detector and the slope), if it is bigger than a certain angle, this detector will touch it and will push the player to the other side by 1 pixel every desired timelapse.
You can see the detector alive by playing my game on the signature, or looking this videos:
[tube]http://www.youtube.com/watch?v=pJFQftlOdH0[/tube]