[GAP Forum] Bug in SemidirectProduct?

[Benjamin Sambale]

Dear forum,

take a look at the following GAP code:

G:=AlternatingGroup(4);
N:=Subgroup(G,[(1,2)(3,4),(1,3)(2,4)]);
H:=DirectProduct(CyclicGroup(2),CyclicGroup(2));
A:=AutomorphismGroup(H);
P:=SylowSubgroup(A,3);
epi:=NaturalHomomorphismByNormalSubgroup(G,N);
iso:=IsomorphismGroups(FactorGroup(G,N),P);
f:=CompositionMapping(IsomorphismGroups(FactorGroup(G,N),P),epi);
SemidirectProduct(G,f,H);

After the command "SemidirectProduct(G,f,H);" GAP returns:

"Error, not ready yet, only finite polycyclic groups are allowed"

But every group in my example is finite polycyclic, even the semidirect 
product would be. I can't imagine, what should be the problem in 
constructing semidirect products.

Thanks for any help,
Benjamin