#240 Segmentation is broken in the Send dialog

[Coleman Brumley]

The functionality for sending segmented messages via
the send dialog is broken.

The example is sendig an RPM via B/IP using an auto
segment size of 50.

The dialog correctly determines that the data I've
entered is too big for a single packet and forces me to
send segment 0 first (with "More Follows" checked)
followed by segment 1 (without "More Follows" checked).

However, when it sends segment 1, the invoke ID is
incremented by 1 and the service choice is incorrect.