Feature to Create a Drupal User from a Profile assumes CiviCRM tables are in the same database as the Drupal ones

After testing out this feature and submitting the form I got the following error:

Sorry. A non-recoverable error has occurred.

Database Error Code: Table 'mike_civicrm.users' doesn't exist, 1146

Return to CiviCRM menu.

Error Details:

Array
(
[callback] => Array
(
[0] => CRM_Core_Error
[1] => handle
)

[code] => -18
[message] => DB Error: no such table
[mode] => 16
[debug_info] =>
SELECT count
FROM users
WHERE LOWER(name) = LOWER('test')
[nativecode=1146 ** Table 'mike_civicrm.users' doesn't exist]
[type] => DB_Error
[user_info] =>
SELECT count
FROM users
WHERE LOWER(name) = LOWER('test')
[nativecode=1146 ** Table 'mike_civicrm.users' doesn't exist]
[to_string] => [db_error: message="DB Error: no such table" code=-18 mode=callback callback=CRM_Core_Error::handle prefix="" info="
SELECT count
FROM users
WHERE LOWER(name) = LOWER('test')
[nativecode=1146 ** Table 'mike_civicrm.users' doesn't exist]"]
)

My Drupal tables are in a different database, but it appears as though this feature assumes the Drupal 'users' table is in the same one as the CiviCRM ones.