In Zabbix Dashboard I've created a trapper item with parameter in its key: event.duration[Method add > 3]

I have script that generates string for sender input to put values for this item.
Its output looks like that:

1. ./send_event_age.sh "app1.d1" "Method add > 3"
   app1.d1 event.duration[Method add > 3] 1399454879 160

When I try to send this output via zabbix sender, it fails:

1. ./send_event_age.sh "app1.d1" "Method add > 3" | /usr/bin/zabbix_sender -z 127.0.0.1 -T -i -
   info from server: "processed: 0; failed: 1; total: 1; seconds spent: 0.000072"
   sent: 1; skipped: 0; total: 1

And then I have such records in server debug log:

1. grep -A6 -B6 'event.duration' /var/log/zabbix/zabbix_server.log
   26007:20140507:163354.271 trapper #1 [processing data]
   26007:20140507:163354.271 trapper got '
   Unknown macro: { "request"}

   '

It seems that the "add" word in item key parameter brokes item key name (event.duration[Method add > 3]).
I tried to close parameter in double quotes, but have no luck with it.