How can I get the "Signal in bus" list in a Bus Creator?

In a Bus Creator dialog box presents a list of signal names as the input. This list is presented as a tree of signals if that are also previously generated as as mux of different signals. How can I get the same sort of list?

I have tried the

get_param('mymodel/Bus Creator','inputSignalNames')

But this only shows the first level of signals. Is there any other parameter in get_param() that allow to get all tree of signals?

For example:

busdemo
get_param('busdemo/Bus Creator','inputSignalNames') 
'<bus1>' 
'bus2<Clock, Pulse, Sine>'

But I would like to get:

|bus1
|--Chirp
|--Const
|
|bus2
|--Clock
|--Pulse
|--Sine

in order to create a structure to access the signal value.

bus1.Chirp
bus1.Const

bus2.Clock
bus2.Pulse
bus2.Sine

I'm using the R2009a version.

Regards,