compiling & installing R devel version on Debian

Hi all.

I'm compiling the devel version of R on Debian GNU/Linux, and installing it into /usr/local tree (instead of default /usr). So:

./configure --prefix=/usr/local/
make
make install

Everything works fine, but when I start R I get the following error messages (traslated from italian, sorry):

Error in dyn.load(x,as.logical(local),as.logical(now)):
     impossible to load the shared library '/usr/lib/R/library/stats/libs/stats.so':
 libR.so:cannot open shared object file: No such file or directory
Error in dyn.load(x,as.logical(local),as.logical(now)):
     impossible to load the shared library '/usr/lib/R/library/methods/libs/methods.so':
 libR.so:cannot open shared object file: No such file or directory

and

package stats in options("defaultPackages") was not found
package methods in options("defaultPackages") was not found


Looks like it's look into the wrong directory tree. But why? Where am I going wrong?

TIA,

Stefano