Lightroom question (about metadata)

[KhronoS]

Ok so I'm using Lightroom for quite a while now. Been putting keywords, and metadata informations, but i ran in a problem. It seems that Lightroom doesn't save the metadata into the file, it only remembers the setting for the particular file (like it does with all other modifications, so that it will not alter the original).
I want to know how to save it, if not directly to the original, at least to save them when i export it or somehow. Any ideas?

Thanks.

 

[KhronoS]

Anyone?