It seems that Designer open only forms; I will investigate it.
I put a test in http://www.logosrl.it/context/test/xfa/s2.pdf
It was made from s2.xdp with Designer; it was uncompressed with pdftk.
I try to replicate it with s2-0001.tex, but I have a problem: I don'know how to to group fields Briefly,I have subform modulo1 subform unnamed field Campo1 field Campo2 field Somma Ie modulo1 contains unnamed which in turn contains Campo1,Campo2,Somma .
But with context I have made 3 distinct groups field Campo1 field Campo2 field Somma and this is not what I need.