Using hooked up internet explorer object

Hi i want to save an html documnet in my hooked up explorer object, i want it to be done automatically without bothering the user, and i want it to save it as mht and NOT html

i tried to do it myself with the following code but it seems like the explorer is still asks for OK and saves it as HTMl file although the ending is of an mht file...
please help me

the code:
after creating the object of the explorer (named MIE as mshtmldocvw and successfully entering a site ....)

MIe.ExecWB(OLECMDID_SAVEAS, OLECMDEXECOPT_DODEFAULT & OLECMDEXECOPT_DONTPROMPTUSER, "C:\Veryinteresting.mht")