Troubles during Gpredict controls IC-705

Here I tried to use Gpredict to control IC-705’s frequency, and I set the radio as below:
Host&Port:Same to what I set in rigctld
Radio Type: Simplex TRX
PTT Status: Read PTT
VFO Up/Down: N/A

Then I tried to control frequency, found that radio cannot be in SPLIT mode, that means, the program can only control one of uplink and downlink

So, are there any ways to deal with it? Thanks a lot