inserting commission in risk calculation

Hi

i use this code for calculating the volume per risk:

/// <summary>
/// Returns the amount of volume based on your provided risk percentage and stop loss
/// </summary>
/// <param name="symbol">The symbol</param>
/// <param name="riskPercentage">Risk percentage amount</param>
/// <param name="accountBalance">The account balance</param>
/// <param name="stopLossInPips">Stop loss amount in Pips</param>
/// <returns>double</returns>
public static double GetVolume(this Symbol symbol, double riskPercentage, double accountBalance, double stopLossInPips)
{
return symbol.NormalizeVolumeInUnits(riskPercentage / (Math.Abs(stopLossInPips) * symbol.PipValue / accountBalance * 100));
}

how is it possible to consider symbol commission inside this?

after opening position we can get the commission with position.Commissions but before entering the position how could we get it to insert this formula?

the second point is above code do not consider spread, how could we consider spread in this volume calculation?