Typing Japanese on an English Language PS3

I'm playing on an English language PS3 but do speak intermediate Japanese and would like to toggle between Japanese and English in game.

I've tried looking for solutions online but none of the suggested answers have worked. Some of the answers were posted during the beta phase so I'm wondering if the option to toggle languages was taken out in favour of the auto-translate function.

Here are some solutions I've come across that either don't work or change the language settings completely. (I'm using a Sony PS3 standard GB layout keyboard.)

1. "Change the PS3 system language/game language to Japanese"
2. "Change the keyboard input on your PS3 to Japanese"
3. "Press '~' or shift + '~'"
4. "Press '¬' or shift + '¬'"

Any help of pointers in the right direction would be greatly appreciated!
Thank you!