substring after/substring before

Hi List,

Can I spilit a string into two parts by last space as substring-before(., '

'[last()]) is not getting accurate result. 


Input : 

A. B. C. Surname


Output:

<fnm>A.</fnm>

<snm>B. C. Surname</snm>


Required output

Output:

<fnm>A. B. C.</fnm>

<snm>Surname</snm>


Anybody have any clue???


Thanks

...JSR