Problem with plurals - 'CHARACTERS'

In language/en/common.php is

'CHARACTERS' => array(
1 => '%d character',
2 => '%d characters',
),

In Czech we translate it as

1 => '%d znak', (for 1)
2 => '%d znaky', (for 2-4)
3 => '%d znaků', (for 5 and more)

It's usable for most of the cases, where it is used (I found one case in language/en/search.php), except in counting characters of password and user name in language/en/ucp.php where are lines like this:

'PASS_TYPE_ANY_EXPLAIN' => 'Must be between %1$s and %2$s.',

In this case we use different form for 5 and more characters than is in language/en/common.php

Example:

"Must be between 3 characters and 25 characters."

We should use:

"...between 3 znaky a 25 znaky"

But we have (because of declension):

"...between 3 znaky a 25 znaků"

Last letter is different (y - ů)

I hope it make a sense.

Now I would like to ask if you can add into language/en/ucp.php separate

plural array 'CHARACTERS_XY' => array(

used only for counting characters in password and user name.