Find & Replace using a SOAP Execute to a Mapping Table in Workday

Fairly new SnapLogic user here. I am building a pipeline connecting an ERP system to Workday. I am using the HTTP Client Snap to pull in data from the ERP system. In this call I get a field "account":

When 'account' matches "wd:External_Code" from my Workday SOAP Execute Snap, I need to replace "account" with the value from "Revenue_Category_ID". So in these screenshots, I would need to replace '101-111224' with "RC10638" as seen in the screenshot below. I am having a hard time getting this to work in the Mapper Snap.

In the expression builder, I cannot figure out a way to tell it when 'account' equals "wd:External_Code" and "@wd:type" contains "Revenue_Category_ID", replace with the associated "$".

Anyone know of a way to make this work?