Hmm... Must work on both then, since my maps uses "Center#" and it works as well.
Oh, and MiC, forgot to mention that the map.ini alone will not provide the map with a looping raining sound or the lightning flashes that occurs periodically. Those would need to be done via the scripts.
First, go into the team list and create a new team called "Rain"
Go into scripts via [Edit > Scripts...] and do the following:
> Create a folder called "Rain" under the "Rain" main directory and have the "Group is Active" check box ticked
> Create the following scripts:
>> Constantly Raining
*** IF ***
True.
*** THEN ***
Play Sound 'RainStereoLoop'.
Play Sound 'ThunderAmbienceStereo'.
Sound 'RainStereoLoop' play at 200.00% of full volume.
Sound 'ThunderAmbienceStereo' play at 200.00% of full volume.
Sound 'ThunderStrikesStereo' play at 200.00% of full volume.
>> Start Lightning
*** IF ***
True.
*** THEN ***
Set timer 'Lightning' to expire between 10.00 and 20.00 seconds.
Enable Script 'Time Between Lightning'.
>> Reset Lightning
*** IF ***
True.
*** THEN ***
Set timer 'Lightning' to expire between 15.00 and 30.00 seconds.
Enable Script 'Time Between Lightning'.
>> Time Between Lightning
*** IF ***
Timer 'Lightning' has expired.
*** THEN ***
Set timer 'Flash_Times' to expire between 0 and 4 frames.
Stop timer 'Flash_Times'
Set timer 'Between_Flash_Times' to expire between 0 and 6 frames.
Enable Script 'Reset Lightning'.
>> Lightning
*** IF ***
Timer 'Between_Flash_Times' has expired.
*AND* Counter 'Flash_Times' IS Greater Than 0
*** THEN ***
Fade (0-1) from 0.60 to 0.00 adding toward white. Take 1 frames to increase, hold for 2 fames, and decrease 2 frames.
Set timer 'Between_Flash_Times' to expire between 0 and 5 frames.
Subtract 1 from counter 'Flash_Times'
Play Sound 'ThunderStrikesStereo'.
> All the scripts are to be set as "Script is Active"
> "Start Lightning", "Reset Lightning" and "Time Between Lightning" are set as "Deactivate upon Success"
> All check boxes for the [Active in] "Hard", "Medium" and "Easy" are checked
Or, if you're just extra lazy, just download the following script file and import it into your map in WorldBuilder
Download Attachment: 
Rain.zip
1.96 KB