Currently Being ModeratedNov 6, 2012 6:16 AM (in response to G. Ewald)
The iCloud account is server based and should not be manually created in Lion or ML. If you have problems with it, sign out of iCloud in System Preferences. The account should delete itself from Mail's accounts in preferences. If it doesn't, select the iCloud account you manually created and delete it from Mail.
Sign back into iCloud and check the box to use Mail. The iCloud account will be automatically created for you in Mail.