[Serusers] Setting tm module parameter "fr_inv_timer_avp" more than once during a call

[reticent]

It seems that setting the "fr_inv_timer_avp" parameter more than once
during a call is not possible.

However there is a situation where this is necessary:

1.  VoIP ATA to VoIP ATA call with call forwarding where call forwarded
number is a PSTN destination
To facilitate Call Forward No Answer, the fr_inv_timer_avp is used and
set to a value (say 12 seconds), after this timer hits a failure_block
is run, in this failure block i rewrite the destination and check if
this destination is a PSTN number.  If it is than I would like to change
the fr_inv_timer_avp parameter to somthing higher due to the nature of
PSTN termination but it does not seem to have any effect.

Has anyone experienced this problem and possible found a workaround?

Or maybe this is a known issue

tavis