How to create a fee as a percentage of equity

I am trying to create a fee instead of a commission. The fee would be an annual fee as a percentage of equity and be reflected in the equity. I have attempted to use the custom backtest for this. The following works, but I am only generating the fee when in cash. bo.equity is read only so how can I accrue this fee when not in cash?

    Daily Fee			=	(1-.01)^(1/252);
	
	for (bar=0; bar < BarCount; ++bar)
	{	
		bo.Cash *= Dailyfee;
	}
bo.Cash -= 0.001 * bo.Equity;

Inside your loop.