[NTG-context] definedelimitedtext options

Hi, Another time ;-) I have \definedelimitedtext [abstract] [leftmargin=yes, spacebefore=line, style={\switchtobodyfont[9pt]},after=\normal] and I want to indent more the abstract. What are the options of definedelimitedtext? In the manual there is no mention for that. Is there any way of doing the same as \startnarrower[2*middle,3*middle]? Thanks in advance, Xan.