Rogue Trader Character Creation

Just thought I'd post some notes about your options:

1) Stay with your DH class as normal. Once you get enough XP, you'll eventually become an Ascension class as normal (your transition packages may be more restricted due to your "unique status," but we can work that out once we get closer).

2) Ask for a transition package to a Rogue Trader class. This would represent you giving up on your old career path to specialize in a Rogue Trader one. You'll still have access to your old skills and can spend XP on upgrades from previous levels, but will no longer be able to advance any further in your DH class. You'd start at the first level of your RT class and can work your way up from there. Additionally, you will replace all characteristic advances with the ones in RT, but will be able to purchase a fifth characteristic level (since RT stats usually start 5 higher than DH ones). The cost for each such upgrade will be equal to the last level of that characteristic for your new class.

3) Retire your DH character and reroll an entirely new RT character, using the character creation process in that book.

Note that everyone should simply bump themselves up to 5000 XP for this. There will probably be some XP cost for the transition package option, but it will include compensating benefits, so don't get your panties in a knot over it (basically, it would be to cover the cost of the new stuff you'd get from your new class).