No gerb is right.

The original poster specified that he wanted Japanese pronunciation. The word "cross" as we native speakers say it is not possible in Japanese phonetics. And also there is consistency to think of. If you are going to start with the Japanese katakana, regardless of where it came from, and romanize that, you can't just randomly throw in English words.

And on that subject as well, you can't just assume that a certain word in katakana was originally intended as "such and such" original English (or other language) word. Not all words that happen to be written in katakana necessarily came from non-japanese words either nor are they always based on pronunciation. It is just as common for the katakana word to be based on the spelling of the original loan word.

This is a really frustrating aspect that I've thought about a lot and the earliest flame wars I remember go back to the old Aeris/Aerith Barret/Bullet thing...
Several things need to be considered:

1. Was the person/place/thing that is written in katakana just meant as an approximate pronunciation of a specific English word?
(ex. ストーン・Stone / ファイヤ・Fire) Those words are not used in the language to describe the concept of stone and fire. If you were to see such words written as text anywhere (who knows.. maybe in a movie title or something) it should be obvious what the original word is. In this case, I think it is acceptable to translate as the actual English word that it was based off.

2. Was the person /place/thing that is written in katakana a shortened or compound version of one or more existing Japanese words?
- The example I'm going to give has nothing to do with video game text. It is just to illustrate the point.-
ドタキャン is used a lot especially in mails to describe the concept of canceling at the last minute. It is derived from the Japanese words 土壇場 and キャンセル where the first (dotanba) means "at the last minute" and the second (kyanseru) means "cancel". What if this was a skill or option in some dating sim? Do you translate as "No show", "Last minute cancellation", or just say "Dotakyan" and expect people to figure out what it means? In these cases, I would choose to focus on the meaning and shorten it as much as possible while still keeping the nuance if possible.

3. Was the person/place/thing that is written in katakana definitely not a Japanese word but the correct English is debatable? Here we are back at Aerith vs. Aeris. The problem in these situations is that with the katakana provided (エアリス), unless the developer reveals somewhere what name this came from, there are a lot of ways to go. Not to mention that maybe they never based it off a real English name. It could have just been made up because they liked how it sounds! Then make things even more confusing by taking the katakana that everyone assumes was based of some "real" English and then the developer simply romanizes it in a manual and causes a huge uproar! Aerith has aesthetic appeal (imo) and is just as close to the katakana pronunciation as Aeris is. In these cases, there will be people in both camps arguing over which is the TRUE, REAL, ORIGINAL spelling but the actually isn't one. The katakana version IS the original since it was based on nothing.

Well there are 3 quick examples of the struggles faced when translating katakana words. You have to take them case by case and there will always be someone that disagrees.
In short, going from English to katakana is like shrinking an image to half its resolution. It's somewhat recognizable but if you never saw the original, you will never know what is missing. (But you can guess :p )

That was a long post. lol