Add Map Layers tool - child layers ignored

Folks,

The Add map Layers tool is working well for us here, as we have a number of cross agency map services being loaded up nicely. One problem is that the map service may have 2+ layers in it.... for example we have hydrants, and hydrant coverage as two layers in the map service we add, and we cannot turn them on/off individually...... 

Not sure if this is an inherent bug - or the tool was designed to add only one map layer per service (which for us means looking at a number of extra map services)??

can this tool be enhanced to respect whatever layers are added to the client - not just the top level service at the only 'layer' that is abled to be toggled on or off?

cheers

Gareth