InfoPath Dev

I have developed total of 5 web enabled forms and they are working properly in miscrosoft office share point server 2007. These pages use web services to retrieve data from database to populate dropdown list boxes and these are working correctly too. After the user save the form, i would like to send email notification to the list of users. Here are some of my questions that i am not clear of how to write implementation for:

1. I have a dropdown list box at the end of form allows the user to select the list of email addresses the email notification will be send too. I notice that the dropdown list won't allow me to select more than one item, is there a work around for it?

2. I created a web service that responsible for sending emai using smtp mail server because there are other stuff that i would like to do before the email is sent such as getting a default list of users from the webconfig files, create a custom mail message, getting requestor credential info (full name, email address, userid..) and so on. I Added a submit button to my infopath form and would like to write the implemention code inside FormEvents_Submit event to do the following: First allow the user to save the form utilize the build save function, second calling my web service (which has been convert to udcx file).

3. Currently all of my forms, which use web service to retrieve data for those dropdown list boxes and they don't work under intenet explorer on windows vista, can someone tell me why? There seem to be some kind of security issues. Those forms worked fine on other web browsers like firefox, safari under windows vista but not IE. Those forms are working perfectly under IE on windows xp.

thank you in advance for your help.

1) Can't do multi-select boxes in browser-enabled forms.  I would recommend a different way of choosing users, such as the Contact Selector control.  This uses AD names to resolve users just like the global address list in Outlook.  Then, you can use the double-eval trick to iterate through the list of names chosen and build your email recipients list from this easily.  Refer to my blog below, and click on the link reference to Alec Pojidaev, since he has the double-eval trick for the Contact Selector box (I did provide input to it on this very forum).

2) Do you really have to use a web service to send that email?  I think you can do all of that stuff you mentioned without any code or custom web services, but rather by leveraging the built-in UserProfileService exposed by MOSS itself.

3) No clue there.