Firefox Textarea Focus

[Sedoc94]

#include <FF.au3>

_FFConnect(Default, Default, 3000)
_FFCmd('.forms[5].elements[50].focus()')

I want to focus on the only <textarea> there is on the loaded page I have in FireFox.

The thing is that the amount of form elements is dynamic, so the index of it changes all the time.

It however does got a static name and title attribute.

Can anybody help me out to get this working?

Thanks!