Urgently Need assistance with relating Data in Power BI

Hello,

I am hoping someone can assist me figure out how to complete the report I am developing.  The report is an Aging Report that needs to show Multi Currency from a table as of the exact date chosen by the end user and put that exchange rate into the summary for the customer record.

I have two Datasets:

BSA00-MC - This is a Multi Currency table that has Curency ID, Exchange Rate, and Exchange Date

BSA00-RMMC - This is a dataset pulling in 89k individual records from our Accounts receivable module.  It includes every single invoice and every single payment for each customer.

I have successfully made the report so that if an end user chooses a date, they can go back in time and see the correct balances of those customer records as of the date they choose.

What I need to do, is on all of those Open balances , be able to match the currency ID , with the Exchange rate as of the specific date the user chooses. However The exchange Rate SUMS up and gives the wrong exchange rate.

What I need is a Vlookup()  function to look at the current Currency ID, look into the BSA00-MC table and extract the exchange rate for that Particular currency ID.

I have two filters on the page level of the report. 

First Filter - Posting Date from BSA00-RMMC is <= The date I put in the filter

Second Filter -  Exchange Date from BSA00-MC = The exact date I enter in the filter.

The Problem is I can not create a relationship in SQL as the Currency rate is determined by the date the users chooses when running the report. So I need to Bring Both datasets into Power BI.

IF I relate the Records on Currency ID, then the balances are all wrong becouse the filter on MultiCurrency limits the recordset.

I only need the Exchange Rate on the TOP table where I have filtered out all 0 balances so that the Exchange rate is calculated JUST on the open balances as seen in the TOP table.

Can this even be accomplished in Power BI?    It Works well in SSRS becouse I can use a parameter when loading the dataset and also filter out all Exchange Rates based on the report date.