CCR1036 - DMA Radius - Centos PPTP Web Server: Ping Problem

Hi,
I have a CCR1036 with hotspot and pppoe enabled. So, I use DMASoftLab as RADIUS. I have installed DMA in web server, running Centos.

I have connected CCR1036 with Centos, using PPTP. I use 192.168.90.1 for Centos and 192.168.90.200 for CCR1036.

The hotspot devices of my network are using 172.19.0.0/22 subnet and CCR is at 172.19.0.1.

My problem:
When I ping from Centos to 192.168.90.200 everything is fine, but when I ping from Centos to any IP of 172.19.0.0/22 subnet, there are no results.

How could I ping my hotspot antennas (using 172.19.0.0/22 subnet) from Centos, over PPTP?

Thanks in advanced.

Make sure that monitored hosts are logged in to HotSpot.