Adding a threshold line (horizontal line) to the graph

[Kabelok]

How do I add the horizontal line to my graphs. I have tried by creating a new graph template Item and the RRD tool output is " HRULE:5#FF0000FF:'Threshold ( 50 )' "
The line is created with the color I have chosen but the problem is the line always appears at the bottom at zero no matter the threshold value I put. Can anybody help

I am using cacti Version 0.8.8b