Sending HTML Mails using SO_DOCUMENT_SEND_API1

Dear all,

we were using SO_DOCUMENT_SEND_API1 to send plain text e-mail replies to participants of an incentive program. Now the customer wants to send HTML mails. Customer has provided HTML templates for the mails, and the text always is the same, only slight changes in regard to the particpants number occur. Has anybody ever performed sending HTML formated mails without using SmartForms?

Thanks for your help!

Kind Regards

Chris