diff --git a/pain/api.go b/pain/api.go
index 686b10a..fe6a043 100644
--- a/pain/api.go
+++ b/pain/api.go
@@ -1,7 +1,7 @@
 package pain
 
 import (
-	//	"fmt"
+	"fmt"
 	"time"
 )
 
@@ -66,9 +66,6 @@ func (d *Document) SetMeta(creditorName, creditorAddr1, creditorAddr2, creditorI
 
 func (d *Document) Finalize(msgId string) error {
 	// GroupHeader:
-	//   Calculate CtrlSum
-	//   Set Timestamp
-	//   Set number of transactions
 	//   Set msgId
 
 	/*
@@ -80,8 +77,12 @@ func (d *Document) Finalize(msgId string) error {
 		}
 	*/
 
-	//csum := 0.0
+	csum := 0.0
 	d.Contents.GroupHeader.MessageId = msgId
+	d.Contents.GroupHeader.Timestamp = time.Now().Format("2006-01-02T15:04:05")
+	d.Contents.GroupHeader.NumTx = fmt.Sprintf("%d", len(d.Contents.PaymentInformation[0].Transactions))
+	d.Contents.GroupHeader.Sum = fmt.Sprintf("%.2f", csum)
+	d.Contents.PaymentInformation[0].Id = msgId
 
 	return d.Valid()
 }
diff --git a/pain/pain.go b/pain/pain.go
index 04345cd..bbdd705 100644
--- a/pain/pain.go
+++ b/pain/pain.go
@@ -47,6 +47,11 @@ func (p *PainXML) Valid() error {
 	if len(p.PaymentInformation) < 1 {
 		err = append(err, "no payment information")
 	}
+	for i, pi := range p.PaymentInformation {
+		if e := pi.Valid(); e != nil {
+			err = append(err, fmt.Sprintf("payment information at %d has errors: %v", i, e))
+		}
+	}
 
 	if len(err) > 0 {
 		return fmt.Errorf("pain XML not valid: %v", strings.Join(err, ", "))
@@ -115,12 +120,13 @@ type PartyIdSEPA1 struct {
 }
 
 type PartyIdSEPA3 struct {
-	Id PartySEPA2 `xml:"Id"`
+	// Embed PartySEPA2, because we do not need another level of <Id>
+	PartySEPA2
 }
 
 func NewPartyIdSEPA3(id string) PartyIdSEPA3 {
 	return PartyIdSEPA3{
-		Id: PartySEPA2{
+		PartySEPA2{
 			PrivateId: PersonIdSEPA2{
 				Other: RestrictedPersonIdSEPA{
 					Id: id,
@@ -134,7 +140,7 @@ func NewPartyIdSEPA3(id string) PartyIdSEPA3 {
 }
 
 func (p *PartyIdSEPA3) Valid() error {
-	return p.Id.Valid()
+	return p.Valid()
 }
 
 type PersonIdSEPA2 struct {
@@ -166,7 +172,7 @@ func (r *RestrictedPersonIdSEPA) Valid() error {
 }
 
 type RestrictedPersonIdSchemeNameSEPA struct {
-	Party string `xml:"Prty"` // IdentificationSchemeNameSEPA
+	Party string `xml:"Prtry"` // IdentificationSchemeNameSEPA
 }
 
 func (r *RestrictedPersonIdSchemeNameSEPA) Valid() error {
diff --git a/pain/pain_regexp.go b/pain/pain_regexp.go
index 1c8cc3a..2441658 100644
--- a/pain/pain_regexp.go
+++ b/pain/pain_regexp.go
@@ -21,6 +21,8 @@ var (
 	IBAN2007Identifier             = regexp.MustCompile(`[A-Z]{2,2}[0-9]{2,2}[a-zA-Z0-9]{1,30}`)
 	RestrictedPersonIdentifierSEPA = regexp.MustCompile(`[a-zA-Z]{2,2}[0-9]{2,2}([A-Za-z0-9]|[\+|\?|/|\-|:|\(|\)|\.|,|']){3,3}([A-Za-z0-9]|[\+|\?|/|\-|:|\(|\)|\.|,|']){1,28}`)
 	BICIdentifier                  = regexp.MustCompile(`[A-Z]{6,6}[A-Z2-9][A-NP-Z0-9]([A-Z0-9]{3,3}){0,1}`)
+
+	CountryCode = regexp.MustCompile(`[A-Z]{2,2}`)
 )
 
 var (
@@ -28,6 +30,7 @@ var (
 		"BIC":              BICIdentifier,
 		"CreDtTm":          ISODateTime,
 		"CtrlSum":          RestrictedDecimalNumber,
+		"Ctry":             CountryCode,
 		"EndToEndId":       RestrictedIdentificationSEPA1,
 		"IBAN":             IBAN2007Identifier,
 		"Id":               RestrictedPersonIdentifierSEPA,
diff --git a/pain/payment_information.go b/pain/payment_information.go
index dabfe98..4943476 100644
--- a/pain/payment_information.go
+++ b/pain/payment_information.go
@@ -43,6 +43,9 @@ func (pmt *PmtInf) Valid() error {
 	if e := pmt.SchemeId.Valid(); e != nil {
 		err = append(err, fmt.Sprintf("payment scheme id not valid: %v", e))
 	}
+	if len(pmt.Transactions) == 0 {
+		err = append(err, fmt.Sprintf("need at least 1 transaction"))
+	}
 
 	if len(err) > 0 {
 		return fmt.Errorf("payment info (Id: %q) not valid: %v", pmt.Id, strings.Join(err, ", "))