[Xymon] Custom Graphs with 60 seconds step in rrd file.

Hi,

I need to change 300 seconds to 30 seconds interval in the rrd file. With this file i will have a custom graph and 60 seconds interval

1. I try with the rrddefiniions.cfg, but don' work the file is recreated with step = 300

[test] -s 60 RRA:AVERAGE:0.1:1:120 RRA:AVERAGE:0.5:5:576 RRA:AVERAGE:0.5:30:576 RRA:AVERAGE:0.5:120:576 RRA:AVERAGE:0.5:1440:576

2. i try rrdtool rrdtune --step = 60 test.rrd but there is not this option in my rrdtune command

Is there another procedure to change step to 60 seconds for a custom script/graph? Thanks,