[otrs] emails with large attachments takes very long

hi, first my setup: otrs 2.4.7 win 2003 mssql 2008 perl 5.10 apache 2.2.10 mod_perl 2.0.4/dev we are experiencing that sending emails with large attachments (> 5MB) through otrs takes very long. i am talking about 2 minutes or even more... 4 minutes when the attachment ist about 10MB. i tried to change the storage placement from DB to FS, but it didn't change anything. unfortunately i don't get any more specific informations in the log files. does anyone have some similar issues or maybe someone of you guys has a solution to this problem ? thanks for your help. regards, patrick.