Index: trunk/core/kernel/utility/formatters.php
===================================================================
diff -u -r1803 -r1814
--- trunk/core/kernel/utility/formatters.php	(.../formatters.php)	(revision 1803)
+++ trunk/core/kernel/utility/formatters.php	(.../formatters.php)	(revision 1814)
@@ -935,7 +935,14 @@
 				case 2: // US/UK
 					$major = $object->GetDirtyField($field.'_a');
 					$minor = $object->GetDirtyField($field.'_b');
-					$value = $major / 2 + $minor / 32;
+					if($major === '' && $minor === '')
+					{
+						$value = null;
+					}
+					else 
+					{
+						$value = $major / 2 + $minor / 32;
+					}
 				break;
 				default:
 			}
@@ -951,8 +958,16 @@
 			switch( $regional->GetDBField('UnitSystem') )
 			{
 				case 2: // US/UK
-					$major = floor( $value / 0.5 );
-					$minor = ($value - $major * 0.5) * 32;
+					if($value === null)
+					{
+						$major = null;
+						$minor = null;
+					}
+					else 
+					{
+						$major = floor( $value / 0.5 );
+						$minor = ($value - $major * 0.5) * 32;
+					}					
 					$object->SetDBField($field.'_a', $major);
 					$object->SetDBField($field.'_b', $minor);
 				break;