quantmod: how to add custom timeseries (addTA?)

Dear members

I'm working with quantmod charts and I should add a timeseries (lowest  
low of the last 55 days) with the same length as the original  
observations. It works fine with addTA(), but quantmod puts a new  
indicator below the chart. But I want to force quantmod to put the  
data in the same indicator as for example the OHLC series.

Thank you, Michael Zak