SPI API IP address change

Greetings,
I’m trying to change module IP address through ISP API mode (AP=1) but withouth any success so far. It works in transparent mode with text AT commands.
Same situation is with IP Address Mask.
Other AT commands are working correctly and data are going through wifi in isp api mode as well.

Data sent to module:
0x7E 0x00 0x08 0x08 0x01 0x4D 0x59 0xC0 0x81 0x0B 0x30 0xD4
Response:
0x7E 0x00 0x05 0x88 0x01 0x4D 0x59 0x01 0xCF // 0x01 after 0x59 means “error”
Module doesn’t report “Invalid Command” or “Invalid Parameter”. Where is problem?

Is it possible to find more detailed AT commands description than in module manual? (http://ftp1.digi.com/support/documentation/90002124_D.pdf)

I also modified firmware file so IP address can be changed and saved in X-TCU now. But still no changes.

Module:
http://www.digi.com/products/wireless-wired-embedded-solutions/zigbee-rf-modules/point-multipoint-rfmodules/xbee-wi-fi#overview

Solved. Address must be sent as string.