Due to the differences between the free hosted blogs offered at wordpress.com and the self-hosted and self-installed version of WordPress supported here, you should probably ask WordPress.com Support instead.
Yea, you can’t customized any code on blogs hosted on wordpress.com. What you would like to do is simply not possible with them, you will need to use shared hosting via some other hosting provider.
oh oke thx ! I move it to the other forum then. Hmm any suggestions, because i just paid 99 euros for a year of wordpress :/
They will be able to help with those questions at wordpress support linked above. I don’t know whether they would refund you or not.