diff --git a/Phys/B2KShh/job/selection.py b/Phys/B2KShh/job/selection.py
index 660adbd..bbf106e 100644
--- a/Phys/B2KShh/job/selection.py
+++ b/Phys/B2KShh/job/selection.py
@@ -38,24 +38,39 @@
 	'B2KKKS'   : {'h1': 'K',  'h2': 'K',  'KS': 'KS'},
 }
 
+def hypoForProduction(source):
+	if '2Lcpi-KS0p' in source and 'MC' in source:
+		hypo = 'B2ppiKS'
+	elif '2pKKS0' in source and 'MC' in source:
+		hypo = 'B2pKKS'
+	elif '2ppiKS0' in source and 'MC' in source:
+		hypo = 'B2ppiKS'
+	if not hypo and 'MC' in source:
+		raise Exception('DANGER: cannot find truth matching hypotesis')
+	return hypo
 
-def truth_match_string(source, hypo):
+
+def truth_match_string(source):
+	hypo = hypoForProduction(source)
 	string  = '('
-	mother = 'MOTHER'
+	mother = {  'h1': 'MOTHER',
+				'h2': 'MOTHER',
+				'KS': 'MOTHER',  }
 	b_id = truth_match['Lb']
 	if 'Lc' in source:
-		mother = 'GDMOTHER'
+		mother['h1'] = 'GDMOTHER'
+		mother['KS'] = 'GDMOTHER'
 	if 'Xib0' in source:
 		b_id = truth_match['Xib0']
 	for h in ['h1', 'h2', 'KS']:
-		string += ' && %s_TRUEID == %s' % (h, truth_match[hypos[hypo][h]])
-		string += ' && %s_%s_TRUEID == %s' % (h, mother, b_id)
+		string += ' && abs(%s_TRUEID) == %s' % (h, truth_match[hypos[hypo][h]])
+		string += ' && abs(%s_%s_TRUEID) == %s' % (h, mother[h], b_id)
 	string += ')'
 	string = string.replace('( &&', '(')
 	return string
 
 
-def make_sel_strings(source, recotree):
+def make_sel_strings(source):
 	sel_strings = {
 		'L0'           : '(L0HadronDecision_TOS || L0Global_TIS)',
 		'HLT1'         : 'Hlt1TrackAllL0Decision_TOS',
@@ -77,7 +92,8 @@
 	else:
 		raise Exception('DANGER: problem with file name parsing and trigger conditions!')
 	
-	sel_strings['TruthMatch'] = truth_match_string(source, recotree)
+	sel_strings['TruthMatch'] = truth_match_string(source)
+	#print sel_strings['TruthMatch']
 	return sel_strings
 
 
@@ -155,12 +171,13 @@
 		print '\tMaking directory %s ...' % t.location
 		outfile.mkdir(t.location, t.location)
 	outfile.cd(t.location)
-	sel_strings = make_sel_strings(source, t.name)
+	sel_strings = make_sel_strings(source)
 	t.cptree = t.tree.CopyTree(' && '.join([sel_strings[sel_name] for sel_name in sel_names]))
 	n_new, n_old = t.cptree.GetEntriesFast(), t.tree.GetEntriesFast()
 	print '\t Copying {0}/{1} tree: {2:.1%} out of {3} events selected...'.format(t.location, t.tree.GetName(), n_new / n_old, n_old)
 	t.cptree.SetDirectory(outfile.GetDirectory(t.location))
-	t.cptree.AutoSave()
+	if t.cptree.GetEntries() > 0:
+		t.cptree.AutoSave()
 	#clones.append(t.tree.CopyTree(' && '.join([sel_strings[sel_name] for sel_name in sel_names])))
 #for c in clones:
 #	c.AutoSave()