Actually i am playing a rogue trader. I want to make him good at close combat and took the talent Two Weapon Wealder (Melee). More melee talents will follow. I am not sure if ranged combat will make a good support and if i should also take Two Weapon Wealder (Ballistic). Has anyone made some experiences with both talents?

You should go for Exotic Weap Training and buy a full set of "Digital Lasers! Better yet, buy a Jokaero!!

I love the sword + pistol combo. Dual wielding melee weapons can produce a bit more damage, but sword and pistol gives you more versatility. Last time I played a Rogue Trader, I didn't even feel the need to acquire any better weapons because my plasma pistol and my power sword were doing great all along.