Index: source/blender/include/BIF_editsima.h
===================================================================
--- source/blender/include/BIF_editsima.h	(revision 10728)
+++ source/blender/include/BIF_editsima.h	(working copy)
@@ -52,6 +52,7 @@
 void borderselect_sima(short whichuvs);
 void mouseco_to_curtile(void);
 void mouse_select_sima(void);
+void select_invert_tface_uv(void);
 void select_swap_tface_uv(void);
 void mirrormenu_tface_uv(void);
 void mirror_tface_uv(char mirroraxis);
Index: source/blender/src/editsima.c
===================================================================
--- source/blender/src/editsima.c	(revision 10728)
+++ source/blender/src/editsima.c	(working copy)
@@ -430,6 +430,38 @@
 	else if(mode==2 || mode==3) BIF_undo_push("Align UV");
 }
 
+void select_invert_tface_uv(void)
+{
+	Mesh *me;
+	MTFace *tface;
+	MFace *mface;
+	int a;
+	
+	if( is_uv_tface_editing_allowed()==0 ) return;
+	me= get_mesh(OBACT);
+	mface= me->mface;
+
+	for(a=me->totface, tface= me->mtface; a>0; a--, tface++, mface++) {
+		if(mface->flag & ME_FACE_SEL) {	
+			if(tface->flag & TF_SEL1) tface->flag &= ~TF_SEL1;
+			else tface->flag |= TF_SEL1;
+
+			if(tface->flag & TF_SEL2) tface->flag &= ~TF_SEL2;
+			else tface->flag |= TF_SEL2;
+
+			if(tface->flag & TF_SEL3) tface->flag &= ~TF_SEL3;
+			else tface->flag |= TF_SEL3;
+
+			if(tface->flag & TF_SEL4) tface->flag &= ~TF_SEL4;
+			else tface->flag |= TF_SEL4;
+		}
+	}
+
+	BIF_undo_push("Invert UV");
+
+	allqueue(REDRAWIMAGE, 0);
+}
+
 void select_swap_tface_uv(void)
 {
 	Mesh *me;
Index: source/blender/src/header_image.c
===================================================================
--- source/blender/src/header_image.c	(revision 10728)
+++ source/blender/src/header_image.c	(working copy)
@@ -524,6 +524,9 @@
 	case 1: /* Select/Deselect All */
 		select_swap_tface_uv();
 		break;
+	case 9: /* Select Inverse */
+		select_invert_tface_uv();
+		break;
 	case 2: /* Unlink Selection */
 		unlink_selection();
 		break;
@@ -591,6 +594,8 @@
 
 	uiDefIconTextBut(block, BUTM, 1, ICON_BLANK1, "Select/Deselect All|A", 0, yco-=20, menuwidth, 19, NULL, 0.0, 0.0, 0, 1, "");
 
+	uiDefIconTextBut(block, BUTM, 1, ICON_BLANK1, "Inverse", 0, yco-=20, menuwidth, 19, NULL, 0.0, 0.0, 0, 9, "");
+
 	uiDefIconTextBut(block, BUTM, 1, ICON_BLANK1, "Unlink Selection|Alt L", 0, yco-=20, menuwidth, 19, NULL, 0.0, 0.0, 0, 2, "");
 	
 	uiDefBut(block, SEPR, 0, "", 0, yco-=6, menuwidth, 6, NULL, 0.0, 0.0, 0, 0, "");