If you can supply a default value for your selects, then you can use the same approach for unchecked check boxes which requires a hidden input before the actual element, as these don't post a value if left unchecked:
<input type="hidden" name="myfield" value="default" />
<select name="myfield">
<option value="default" selected="selected">Default</option>
<option value="othervalue">Other value</option>
<!-- ... //-->
</select>
This will actually post the value "default" (without quotes, obviously) if the select is disabled by javascript (or jQuery) or even if your code writes the html disabling the element itself with the attribute: disabled="disabled".