PATINDEX / LIKE - How To Do A Regular Expression In One Of These?

Hi

I have a table which stores a big chunk of html text, which I have to search for and replace some strings.
How can I write a query that makes use of regular expressions to do the following:

Below is a block of example text
======================================================================
" src="http://aaaa/bbbb/cccc.nsf/blind%2010x10.gif?OpenImageResource" width=10> <img height=10 alt="" src="http://aaaa/bbbb/cccc.nsf/blind%2010x10.gif?OpenImageResource" width=10><img height=11 alt=""
http://aaaa/bbbb/cccc.nsf/blablablabla?OpenDocument src="http://aaaa/bbbb/cccc.ns http://aaaa/bbbb/cccc.nsf/d8d4f0dfa09ba71142256cc50040ee51/ee9b4493dac727be422571c30027df61? OpenDocument" target=_self>

======================================================================

Now I want to search and replace the string that is highlighted in red with something like "FOUND"
The below string is what I want to search for - I will used PATINDEX on the string below to find the start index of the string in the body, and then I will add on 114 to the when doing a replace:

'%http://aaaa/bbbb/cccc.nsf/%some guid%/%some guid%?OpenDocument%'


For example

REPLACE
(
TheField,
SUBSTRING

(
TheField,
PATINDEX(''%http://aaaa/bbbb/cccc.nsf/%some guid%/%some guid%?OpenDocument%', TheField),
,114

)
,
'FOUND'
)



QUESTION:

what would the regular expression be and how does one type it in the query?
I tried something like the below but it does not work, please advise .....
[a-z][0-9]{32} %/% [a-z][0-9]{32}