Question: changing variable in integral

Hello,

I am trying to change the variable in an integral and I have two problems with it:

My first problem is that I can't get the integrand of the new integral with GetIntegrand when I use IntegrationTools[Change] :

restart;

a1:=Int(1/(2*A),x=-A..A);

D1:=IntegrationTools[Change](a1,x=20*log[10](u));

# It is ok, but I would like to get the new integrand:

IntegrationTools[GetIntegrand](D1);

# it doesn't work, because some parts of the new integrand are outside the integral and GetIntegrand can't handle this.

# Fortunately with PDEtools[dchange]  Maple can do it:

D2:=PDEtools[dchange](x=20*log[10](u),a1);

IntegrationTools[GetIntegrand](D2); # ok.

 My second problem is that when I use a constant (K) in the expression of the variable transformation, the Change can't handle it:

a1:=Int(1/(2*A),x=-A..A);

D1:=IntegrationTools[Change](a1,x=K*log[10](u))  assuming AndProp(K::realcons,K>1);

# it gives an error message.

Thanks you for your comment in advance.