Index: t/update/belongs_to_create.t
===================================================================
--- t/update/belongs_to_create.t	(revision 0)
+++ t/update/belongs_to_create.t	(revision 0)
@@ -0,0 +1,41 @@
+use strict;
+use warnings;
+use Test::More;
+
+use HTML::FormFu;
+use lib 't/lib';
+use DBICTestLib 'new_schema';
+use MySchema;
+
+my $form = HTML::FormFu->new;
+
+$form->populate({
+    elements => [
+        {
+            name => 'band',
+        },
+        {
+            type => 'Block',
+            nested_name => 'manager',
+            elements => {
+                name => 'name',
+            }
+        }
+    ]
+});
+
+my $schema = new_schema();
+
+my $rs = $schema->resultset('Band');
+my $band = $rs->new_result({});
+
+$form->process({ band => 'The Foobars', 'manager.name' => 'Mr Foo' });
+
+$form->model('DBIC')->update($band);
+
+$band->discard_changes;
+
+is($band->band, 'The Foobars');
+is($band->manager->name, 'Mr Foo');
+
+done_testing;
\ No newline at end of file
Index: t/lib/MySchema/Band.pm
===================================================================
--- t/lib/MySchema/Band.pm	(revision 1672)
+++ t/lib/MySchema/Band.pm	(working copy)
@@ -16,7 +16,7 @@
 
 __PACKAGE__->set_primary_key("id");
 
-__PACKAGE__->belongs_to( manager => 'MySchema::Manager', 'id' );
+__PACKAGE__->belongs_to( manager => 'MySchema::Manager' );
 
 __PACKAGE__->has_many( user_bands => 'MySchema::UserBand', 'band' );
 
Index: lib/HTML/FormFu/Model/DBIC.pm
===================================================================
--- lib/HTML/FormFu/Model/DBIC.pm	(revision 1672)
+++ lib/HTML/FormFu/Model/DBIC.pm	(working copy)
@@ -477,6 +477,7 @@
 
         }
         elsif ( defined $block && ref $params eq 'HASH' ) {
+            $dbic->$rel(undef) unless($dbic->$rel);
             my $target = $dbic->find_related( $rel, {} );
 
             if ( !defined $target && grep { length $_ } values %$params ) {
@@ -492,6 +493,10 @@
                     nested_base => $rel,
                     from        => $dbic->result_class,
                 } );
+            unless($dbic->$rel) {
+                $dbic->$rel($target);
+                $dbic->update;
+            }
         }
         elsif ( defined $multi_value ) {
             # belongs_to, has_one or might_have relationship