diff --git a/src/Data/NominalAccounts/Beneficiaries/CreateBeneficiaryRequestData.php b/src/Data/NominalAccounts/Beneficiaries/CreateBeneficiaryRequestData.php
index 3a40179..23bab0d 100644
--- a/src/Data/NominalAccounts/Beneficiaries/CreateBeneficiaryRequestData.php
+++ b/src/Data/NominalAccounts/Beneficiaries/CreateBeneficiaryRequestData.php
@@ -36,6 +36,7 @@ class CreateBeneficiaryRequestData extends Data
         public string $countryOfTaxResidence,
         #[DataCollectionOf(AddressData::class)]
         public DataCollection $addresses,
+        public ?bool $isBeneficiary = null,
         #[DataCollectionOf(DigestSignatureData::class)]
         public ?DataCollection $digestSignatures = null,
         public ?string $accountNumber = null,
diff --git a/src/Traits/SignableData.php b/src/Traits/SignableData.php
index 5469193..c718b54 100644
--- a/src/Traits/SignableData.php
+++ b/src/Traits/SignableData.php
@@ -38,7 +38,7 @@ trait SignableData
         // We can't push to DataCollection directly if it's not array-access compatible in all versions,
         // but Spatie DataCollection is usually iterable.
         // Safest way is to reconstruct it.
-        $current = $this->digestSignatures->toCollection()->all();
+        $current = array_values($this->digestSignatures->toCollection()->all());
         $current[] = new DigestSignatureData($signature, 'cms');
 
         $this->digestSignatures = new DataCollection(DigestSignatureData::class, $current);