Service Limits in Purchase Requisitions: Where to Insert Custom Code?

Question

The issue is related to finding a place in SAP logic where a BADI, or, an
enhancement can be implemented when inside transaction ME52N for a
Service Limits type Purchase Requisition where K is the Account
Assignment and B is the Item Category for a Service Limit Purchase
requisition. Especially. or initially, at the point of navigation when
going from (within the Limit Tab) and selecting the Account Assignment
Icon to the right.
By finding a good place to insert custom code in between these two tabs
during navigation I am referring to (1)the actuality of the transaction
breaking into this location, and,(2)a place where the global fields can
be read and changed ie. GL Account Number, Material Group, etc.
I have read, and reviewed several SAP Notes: 496082, 627072 and 551863.
Failed Attempts:
1)I have tried finding BADIs via breakpoints inside of
CL_EXITHANDLER~GET_INSTANCE. None that are found are used and are not ofany help.
2)I have attempted to use various user exits within the following SMODs,to name a few:
MEREQ001 |Customers' Own Data in Purchase Requisition
SAPLF0PR |Requests: Account Determination and Checks
SAPMF02H |Function exit: G/L account master data
V45E0002 |Data transfer in procurement elements (PRreq., assembly)
WDFE0001 |Customer-Specific Determination of Requirements Data
COZF0001 |Change purchase req. for externally processed operation
COZF0002 |Change purchase req. for externally procured component
3)I have implemented various custom enhancements inside of SAP Main
Program SAPLMEREQ inside include LMEREQF09, and a few other LMEREQFXX.
4) We previously used BADI 'ME_PROCESS_REQ_CUST' to satisfy a similar
requirement, but is of no help for this request.
Thank-You,

Answer 1

Custom tags are different than udfs.  Let's stick with udfs.  Your location choices are:
1.  If only one template is going to use it, you can put it in that template.  Otherwise,
2. You can put it in a .cfm file and cfinclude that file whenever you want to call the function, or
3. You can put it into a .cfc.
A little while back, someone ran some tests and posted the results on one of these forums.  The gist of it was that Option 2 would run faster than Option 3.