Hi Michael,
As long as I am working with Alibre (V6) STL Import, was never an option,
and IMHO, should not be an option.
STL Export with Alibre is possible, for example: Rapid prototyping.
With "netfabb Studio Basic":
http://www.netfabb.com/basic.php
it provides mesh edit, repair and analysis capabilities to everyone...
But "reconverting" STL files to solid`s, requires different/specific applications.
10 - 15 MB STL files is the max ~ limit~ for the most "small" converter.
.
As an attachment your STL file
370 KB as Alibre Part
9,55 MB
(The ratio of different amounts of data shows one of the "problems": STL -> Volume)