generate random number in omnet++ ini files without any distribution function

how can i generate random number between 0 and 1 without using any distribution function in my ini file. in fact i want to "0.7s" in this code be random:

**.host1.mytest[*].sendInterval = 0.7s

send interval is also configured in the NED file as follow:

volatile double sendInterval @unit("s") = default(1s);