Your Ubuntu package works well also in Debian Lenny: you only have to change a line into DEBIAN/control file:
$ diff control_old control
6c6
< Depends: libaspell15 (>= 0.60), libc6 (>= 2.4), libexpat1 (>= 1.95.8), libgcc1 (>= 1:4.1.1), libpcre3 (>= 7.4), libstdc++6 (>= 4.1.1), libwxbase2.8-0 (>= 2.8.8.0), libwxgtk2.8-0 (>= 2.8.8.0), libxerces-c28, libxml2 (>= 2.6.27), libxslt1.1 (>= 1.1.18)
---
> Depends: libaspell15 (>= 0.60), libc6 (>= 2.4), libexpat1 (>= 1.95.8), libgcc1 (>= 1:4.1.1), libpcre3 (>= 7.4), libstdc++6 (>= 4.1.1), libwxbase2.8-0 (>= 2.8.7.0), libwxgtk2.8-0 (>= 2.8.7.0), libxerces-c28, libxml2 (>= 2.6.27), libxslt1.1 (>= 1.1.18)