How I can enable the interest for the symbols and for specific client?
You can enable the Interest option on symbols that your clients are trading by following these steps:
 From the Backoffice go to the main menu and choose System Options then open the Symbols Settings tab.
 Select the symbol or multi select on the symbols that you wish to enable the interest on.
 Right click and choose Edit/ Edit Selected, and go the Interest (Swap Rates) tab.
 If you checked the first check box then the interest will be enabled for this symbol, In this way it should be enabled for the client from Parameters then general tab option.
 The yearly long interest rate value (for buy positions).The default value is zero, you can change it in percentage like this: let say that you want 5% as interest per year and it should be 0.05.
 The yearly short interest rate value (for sell positions).The default value is zero, you can change it in percentage like this: let say that you want 5% as interest per year and it should be 0.05, and note that this percentage range is from 1 to 1.
 In the Year days drop down list you can change the year days (default value is 365 day) to be calculated in interest formula.
 In the days factor you can define factor for every day to be used in calculating the interest formula (how many time do you need to calculate the interest for this symbol per day).
 The last thing is the interest formula for buy and sell positions which you can control it by modifying the values of the day factor, year days, yearly short (sell) interest rate (affecting sell positions formula) and yearly long (buy) interest rate (affecting buy (positions formula).
