Update PST file location on Logon via Script

Script to update PST File locationsBookmark:Question:
We are running a project to migrate the backend file location for 1000 user created PST files to a new 2008 File server. The server will not re-use the previous server name and we will not be able to use a DNS alias for the old server to point to the new one.

Users have historically used personal folders stored in their networked homedrives (Yes, we know it is not a Microsoft best practise methodology for PST file usage) and we are planning to move all pst files to a decidated PST file server and then update the path location to the pst files with no user impact or intervention.

I am looking at implementing a logon script to remap the pst file to the new location. The workflow will be as follows

Nighttime (After backups complete) robocopy pst files from \\oldserver\homedrive$ to \\newserver\pstdir$
Remove permissions to the source PST file
On user logon - map new network drive (P:\ to the \\newserver\pstdir$ directory (this will be a security locked down folder based on the user's name)
Logon script to query the registry or mapi profile of the user and for every pst file connected (Some users have more than 1) change the path from M:\ (current user homedrive mapping) to P:\ (preserving the rest of the path, for example if a user had M:\MyMail\October-Archive.pst file then the remap should be P:\MyMail\October-Archive.pst)

I am ok for the 1st parts of the problem, but I am stuck on the Logon script, as the value stored in the registry is a hexidecimal string. So I need to query all outlook profiles for the user, compile an array of pst file string locations, decode the strings, rewrite the new path, encode the string and write it back.

I have found a few scripts on the net that in part achieve some aspects of this, but nothing that provides a complete solution.

Mapi profile information is stored in the registry here "HKCU\Software\Microsoft\Windows NT\CurrentVersion\Windows Messaging Subsystem\Profiles"

The key name for a PST file is either "01020fff" "001f6700" (Example below)

HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows Messaging Subsystem\Profiles\Default Outlook Profile\93abdcf58c80884b92c1b8c1b272dc12
    01023414    REG_BINARY    4E495441F9BFB80100AA0037D96E0000
    001f300a    REG_BINARY    6D0073007000730074002E0064006C006C000000
    001f3d13    REG_BINARY    7B00360034003800350044003200360032002D0043003200410043002D0031003100440031002D0041004400330045002D003100300041003000430039003100310043003900430030007D000000
    00033e03    REG_BINARY    21000000
    00033009    REG_BINARY    00000000
    001f3001    REG_BINARY    50006500720073006F006E0061006C00200046006F006C0064006500720073000000
    001f3006    REG_BINARY    50006500720073006F006E0061006C00200046006F006C0064006500720073000000
    01023d0c    REG_BINARY    2BDB2EC4365E81428904AB3D06E7FD3E
    001f3d09    REG_BINARY    4D005300550050005300540020004D0053000000
    00036770    REG_BINARY    00000080
    00036702    REG_BINARY    00000010
    01020fff    REG_BINARY    0000000038A1BB1005E5101AA1BB08002B2A56C200006D737073742E646C6C00000000004E495441F9BFB80100AA0037D96E0000000043003A005C00540065006D0070005C00540065007300740031002E007000730074000000
    001f6700    REG_BINARY    43003A005C00540065006D0070005C00540065007300740031002E007000730074000000
    001f3004    REG_BINARY    0000
    01020ff9    REG_BINARY    636E08EC45E2F449AB50A4F2AB97DDF3