The relevant section in the 46xxsettings.txt file is:
## WMLPROXY specifies zero or one address for an HTTP proxy server that will be used by the
## WML browser, and by the Weather and World Clock applications on the 9621, 9641 and 9670.
## The address can be in dotted-decimal (IPv4), or DNS name format,
## separated by commas without any intervening spaces.
## The value can contain up to 255 characters; the default value is null ("").
## This parameter is supported by:
## 96x1 H.323 R6.0 and later
## 96x1 SIP R6.2 and later
## 96x0 H.323 R1.0 and later
## 96x0 SIP R2.0 and later
## 46xx H.323 R1.71 and later
## SET WMLPROXY proxy.company.com
##
## WMLPORT specifies the TCP port number of the HTTP proxy server specified by WMLPROXY.
## Valid values are 0 through 65535.
## The default value for H.323 software is 8000.
## The default value for SIP software is 8080.
## This parameter is supported by:
## 96x1 H.323 R6.0 and later
## 96x1 SIP R6.2 and later
## 96x0 H.323 R1.0 and later
## 96x0 SIP R2.0 and later
## 46xx H.323 R1.71 and later
## SET WMLPORT 9000
##
## WMLEXCEPT specifies zero or more IP addresses or domains for which
## the HTTP proxy server specified by WMLPROXY will not be used.
## The values are separated by commas without any intervening spaces.
## The value can contain up to 255 characters; the default value is null ("").
## This parameter is supported by:
## 96x1 H.323 R6.0 and later
## 96x1 SIP R6.2 and later
## 96x0 H.323 R1.0 and later
## 96x0 SIP R2.0 and later
## 46xx H.323 R1.71 and later
## SET WMLEXCEPT mycompany.com,135.20.21.20