As the others have said there is no equivilent to sendmail for Windows.

The best solution would be to use a module. This has the problems you stated.

The only real solution I can see it to write your own code that sends the email in a portable way. But this is no simple task.

Sorry I couldn't have been more help and hope you find a solution.

!unlike

"The price if ignorance, which is of course that you must learn from those who know." Socrates (paraphrased)