How do I build my OID tree under my PEN instead of an extension of Net-SNMP?

Question

Currently, my OIDs branch from Net-SNMP using extend, which results in an OID like this:

SNMPv2-SMI::enterprises.8072.1.3.2.4.1.2.1.49.1258

or without the MIB:

.1.3.6.1.4.1.8072.1.3.2.4.1.2.1.49.1258

8072 is Net-SNMP,
49 is the decimal value of an ASCII "1" (an arbitrary name I gave my extension), and
1258 is a 'leaf' on my root OID (49).

Now that I have a PEN, how do I go about making my OID tree under my PEN so that I can execute an snmpwalk that displays:

.1.3.6.1.4.1.<MyPEN>.<MyOIDTree>

OS: Linux (Raspbian)

Answer 1

Partial Solutions:

-Good-
Specify an OID in the extend command (in snmpd.conf) like so:

extend [OID] <extName> </dir/binary> </dir/script>

The OID is optional, however, omitting it will cause the Net-SNMP PEN to be used by default.

In my case, my extend looks like this:

extend .1.3.6.1.4.1.<myPEN> SQL /bin/sh /usr/sbin/MyScript.sh

This produces the following output:

.1.3.6.1.4.1.[PEN redacted].4.1.2.3.83.81.76.1258 = STRING: "My Data"

This is much closer to the desired structure since it is now extending from a custom PEN, though one is now faced with trimming off the .4.1.2.3 and the .83.81.76 (resulting from the extension name 'SQL').

If anyone knows how to remove those, post it as a new answer!

-Better-
Use the pass command:
pass .1.3.6.1.4.1.PEN /bin/sh /home/pi/net-snmp/local/shellCode
Shell code example: passtest

Output:

.1.3.6.1.4.1.PEN.1.0 = STRING: "Hello World!"
.1.3.6.1.4.1.PEN.2.1.2.1 = INTEGER: 9
.1.3.6.1.4.1.PEN.2.1.3.1 = OID: .1.3.6.1.4.1.PEN.99
.1.3.6.1.4.1.PEN.3.0 = Timeticks: (363136200) 42 days, 0:42:42.00
.1.3.6.1.4.1.PEN.4.0 = IpAddress: 127.0.0.1
.1.3.6.1.4.1.PEN.5.0 = Counter32: 9
.1.3.6.1.4.1.PEN.6.0 = Gauge32: 9

This appears to solve both issues, however I am unsure of the extent of its capabilities in comparison to a 'proper' OID tree installation.

-Best- (Complete Solution)
Register OIDs using a MIB...