I understand you wanted to know the margin for your XAGUSD in AUD account. Since you have 1:100 leverage 2.6 lot, you will get 3,099.85 AUD. Please see detailed computation below: 

Formula: 

Required Margin = Trade Size / Leverage * Account Currency Exchange Rate 

Calculation: 

Volume in Lots: 2.6 (One Standard Lot = 100,000 Units) 

Leverage: 100 

Account Base Currency: AUD 

Currency Pair: XAG/USD 

Exchange Rate: 16.45900 (XAG /USD) 

  

Required Margin = 260,000 /100 * 16.45900 

Required margin is 2,139.67 USD 

Convert to your account base currency and that’s equalled to 3,099.85 AUD