Calling assigned subwindow method

[Martin Obongita]

Hi All,
I call a method in a subwindow with the command in the main window:
Do $cinst.$objs.subform.$subinst().$message(cMessage)

How do I call a method in a subform IF I have assigned the classname of the subform?
For example:
Calculate lSubFormName as 'jsSubFormReport'
Do $cinst.$objs.SubForm.$classname.$assign(lSubFormName)
This instantiates the subform ok.
I tried running the line below from the main form and it fails:
Do $cinst.$objs.[lSubFormName].$subinst().$message(cMessage)


Kind regardsMartin Obongita