diff --git a/src/CreditNote.php b/src/CreditNote.php
index 75a418f..90e3bb2 100644
--- a/src/CreditNote.php
+++ b/src/CreditNote.php
@@ -34,6 +34,11 @@ public function setCreditNoteLines(array $creditNoteLines)
 
     /**
      * The xmlDeserialize method is called during xml reading.
+     *
+     * Overrides parent to read CreditNoteTypeCode instead of InvoiceTypeCode.
+     * CreditNotes use CreditNoteTypeCode (e.g., 261 for self-billing credit note)
+     * while Invoices use InvoiceTypeCode (e.g., 389 for self-billing invoice).
+     *
      * @param Reader $reader
      * @return static
      */
@@ -42,7 +47,19 @@ public static function xmlDeserialize(Reader $reader)
         $mixedContent = mixedContent($reader);
         $collection = new ArrayCollection($mixedContent);
 
-        return (static::deserializedTag($mixedContent))
+        $instance = static::deserializedTag($mixedContent)
             ->setCreditNoteLines(ReaderHelper::getArrayValue(Schema::CAC . 'CreditNoteLine', $collection));
+
+        // Read CreditNoteTypeCode (CreditNotes use this instead of InvoiceTypeCode)
+        $creditNoteTypeCode = ReaderHelper::getTagValue(
+            Schema::CBC . 'CreditNoteTypeCode',
+            $collection
+        );
+
+        if ($creditNoteTypeCode !== null) {
+            $instance->setInvoiceTypeCode((int) $creditNoteTypeCode);
+        }
+
+        return $instance;
     }
 }
diff --git a/src/Invoice.php b/src/Invoice.php
index 9a5a957..aa08ecd 100644
--- a/src/Invoice.php
+++ b/src/Invoice.php
@@ -89,6 +89,14 @@ public function setId(?string $id)
         return $this;
     }
 
+    /**
+     * @return string|null
+     */
+    public function getCustomizationId(): ?string
+    {
+        return $this->customizationID;
+    }
+
     /**
      * @param mixed $customizationID
      * @return static
@@ -99,6 +107,14 @@ public function setCustomizationId(?string $customizationID)
         return $this;
     }
 
+    /**
+     * @return string|null
+     */
+    public function getProfileId(): ?string
+    {
+        return $this->profileID;
+    }
+
     /**
      * @param mixed $profileID
      * @return static
diff --git a/src/InvoiceTypeCode.php b/src/InvoiceTypeCode.php
index 26d2910..15a2001 100644
--- a/src/InvoiceTypeCode.php
+++ b/src/InvoiceTypeCode.php
@@ -14,4 +14,8 @@ class InvoiceTypeCode
     public const CORRECTED_INVOICE = 384;
     public const ADVANCE_INVOICE = 386;
     public const SELF_BILLING_INVOICE = 389;
+
+    // Self-billing credit note (UNCL1001 code 261)
+    // Used when the buyer issues a credit note on behalf of the seller
+    public const SELF_BILLING_CREDIT_NOTE = 261;
 }