Depends on how big the backup is. You could use an Execute T-SQL Statement Task to send the email, but I think there's a size limitation on the attachment using this method and it's not very large. Though the issue could be the size limitation in Outlook rather than in SSIS (the base for the maintenance plan wizard).

I would not send a backup file via email anyway. Too easy for it to get corrupted or intercepted or just to plain fail due to backup size. Use a NAS share that only a select few have access to and copy it there. That way you can control access and it is less likely to cause other issues.

I certainly wouldn't want to receive an attachment that large in my inbox. Outlook would freeze while trying to process that.

EDIT: From BOL about sp_send_dbmail - By default, Database Mail limits file attachments to 1 MB per file. For more information, see Database Mail Configuration Wizard.

EDIT 2: It occurs to me you might be talking about the log instead of the actual backup file. If the log, then usually those aren't big. You could send that using the Execute T-SQL Statement Task.