standard way to use shortcuts in l10n

[Jamil Ahmed]

Hello,

Is there any standard for using shortcuts while l10n-ing?
Should I put shorcuts in localize form? or keep same english short cut 
separately in parenthesis?

like, for
msgid "_File"

Should I use,

msgstr "_xx"
or
msgstr "xx (_x)"
or
msgstr "xx (_F)"    <--- this _F will be taken from the msgid's shorcut

xx will be written in my localized character.

Waiting for your valued reply!

Thanks,
`Jamil
L10n: Bengali