Wang Anshi was invited by Song Shenzong to be Primer Minster of Song court from year 1070 . So without approval of Wang Anshi, no proposal or plant to annex Dai Viet to Song Dynasty should been approved.
Two Song guan Shen Ki (Thẩm Khởi) and Liu Ji (Lưu Di) were ordered to mobilize inhabitants (punti people), produce weapons, build many boats and warships, training soldiers...etc to conquer Dai Viet.
Yes, Lý Thường Kiêt (
李常傑; 1019–1105) was a Vietnamese general during the Lý Dynasty
.. and he is regarded as a Vietnamese National hero.
He penned what is considered the first Vietnamese declaration of independence with his poem. It said:
南國山河
南 國 山 河 南 帝 居
截 然 定 分 在 天 書
如 何 逆 虜 來 侵 犯
汝 等 行 看 取 敗 虛
Dịch thơ:
Sông núi nước Nam
Sông núi nước Nam, vua Nam ở
Rành rành định phận tại sách trời
Cớ sao lũ giặc sang xâm phạm?
Chúng bay sẽ bị đánh tơi bời.
sorry, I can't translate into English,