I actually don't believe it is possible. In my experience, Matlab is fairly limited as an activeX server. You might be able to figure something out by surfing around the Mathworks site. If it is possible from VB or VC++ you can probably get something similar to work from LabVIEW.
http://www.mathworks.com/access/helpdesk/help/techdoc/matlab_external/ch07cl12.shtml