Attaching several .txt files as attachment

We are getting somewhere .... Our Batch File which sends .txt files "Inline", split into several Emails in case there is more than one file in the Directory, is working.
blat.exe filename.txt followed by parameters for recipients, signature, log file, etc.
 How do I call Blat in case I want to call all txt files in a directory, and have them all attached to one mail (Not in Body!)?