I have the following problem.

Assume I have an account in USD and I trade two Fx pairs: EURUSD and AUDCHF.

According to my money management I risk n-percent of my account and have a StopLoss.

It is easy to calculate the Quantity of EURUSD for trading;

CashForDeal=Cash* (PercentOfRisk)) / (StopLoss * PairMinVariation)


But to calculate the Quantity of AUDCHF for trading I have to know price of AUDUSD:

CashForDeal=Cash* (PercentOfRisk)) / (StopLoss * PairMinVariation)


Is there any possibility to find out the price of AUDUSD, without adding it to the strategy?