If I'm not mistaken, what you have there is PAL speedup. In Europe, and therefore also in Spain, before the arrival of HD tvs and bluray technology, we used the PAL system, that for technical reasons required all film content to be sped up by roughly 4%.

Harmy's release, on the other hand, conforms to proper film speed, and so you would need to slow down your soundrack to match that.

I would suggest you to take a look at the "How-To's and Technical Discussions" subforum, specifically this thread:

Doctor-Ms-berGuide-for-Full-PAL-to-NTSC-DVD-Conversion-v20/topic/10111/