Hello,

The character entered by typing "C-x 8 RET 794a" for µp is incapable 
of being entered using the chinese-ctlaub input method.

At the following website, the Sidney Lau "Cant. Scheme" has "Canton. 
Syllables" for typing in µp using

* bang
* paang

=> https://humanum.arts.cuhk.edu.hk/Lexis/lexi-mf/search.php?word=µp 
Multi-function Chinese Character Database

-- 
vl