//remember to check for syntax errors before copy-paste-ing!
//this only adds the 7 char-restriction to the register page
add_filter ( 'wppb_register_content_about_yourself3', 'add_char_length', 10, 7);
function add_char_length ($old_pass, $localVar1, $localVar2, $errorVar, $errorMark, $errorVar2, $errorMark2 ){

 return '
<p class="form-password'.$errorVar.'">
<label for="pass1">'. __('Password', 'profilebuilder') .$errorMark.'</label>
<input class="text-input" name="passw1" maxlength="7" type="password" id="pass1" value="'.trim($localVar1).'" />
</p><!-- .form-password -->

<p class="form-password'.$errorVar2.'">
<label for="pass2">'. __('Repeat Password', 'profilebuilder') .$errorMark2.'</label>
<input class="text-input" name="passw2" maxlength="7" type="password" id="pass2" value="'.trim($localVar2).'" />
</p><!-- .form-password -->';
}