Try storing the synthetic device mint payload here

event/sdmint/sdmint.go

@@ -0,0 +1,28 @@
+package sdmint
+
+import "github.com/ethereum/go-ethereum/common"
+
+var Type = "com.dimo.zone.device.synthetic.mint"
+
+type Data struct {
+	Integration Integration `json:"integration"`
+	Vehicle     Vehicle     `json:"vehicle"`
+	Device      Device      `json:"device"`
+}
+
+type Integration struct {
+	TokenID       int    `json:"tokenId"`
+	IntegrationID string `json:"integrationId"`
+}
+
+type Vehicle struct {
+	TokenID      int    `json:"tokenId"`
+	UserDeviceID string `json:"userDeviceId"`
+}
+
+type Device struct {
+	TokenID           int            `json:"tokenId"`
+	ExternalID        string         `json:"externalId"`
+	Address           common.Address `json:"address"`
+	WalletChildNumber uint32         `json:"walletChildNumber"`
+}