AS400 - ProgramCall with SNA-Protocol ?

[heiner weilandt]

hi,
i have a problem to connect from an as/400 (websphere 4) to call an cobol-pgm on another as/400 about the ibm protocol sna.

 
AS400 sys = new AS400(Env.SYSTEM, Env.USER, Env.PASS);
ProgramCall pgm = new ProgramCall(sys);

with tcp/ip it works fine, but over an sna - protocol the as/400 prompt: "unknown host exception"
it is possible to connect over sna ?
thanx
heiner