Integration query to get Shpiment Ship Unit Line Number

The below query doesn't pick the Ship Unit Xid or the Packaged Item Xid as per the given XPaths. I've tried a few combinations of the XPath but in none of the cases the values is getting picked for these XPaths, in the logs they are coming as 'null' everytime.

SELECT S_SHIP_UNIT_LINE_NO FROM S_SHIP_UNIT_LINE WHERE S_SHIP_UNIT_GID='{'VRTX.'||Shipment/ShipUnit/ShipUnitGid/Gid/Xid}' AND PACKAGED_ITEM_GID='{'VRTX.'||Shipment/ShipUnit/ShipUnitContent/PackagedItemRef/PackagedItemGid/Gid/Xid}'

Attaching the sample payload for reference. Please note that I've removed the domain name values intentionally in this XML.