Index: /branches/eam_branches/ipp-20130904/psModules/src/objects/pmSourceMoments.c
===================================================================
--- /branches/eam_branches/ipp-20130904/psModules/src/objects/pmSourceMoments.c	(revision 36299)
+++ /branches/eam_branches/ipp-20130904/psModules/src/objects/pmSourceMoments.c	(revision 36300)
@@ -530,5 +530,9 @@
 	kronRefRadius = MIN(radius, kronRefRadius);
     }
-    source->moments->Mrf = kronRefRadius;
+
+    // if source is externally supplied and it already has a finite Mrf do not change it
+    if (! ((source->mode & PM_SOURCE_MODE_EXTERNAL) && isfinite(source->moments->Mrf))) {
+        source->moments->Mrf = kronRefRadius;
+    }
 
     return true;