I have the USBtinyISP AVR Programmer up and running under the Arduino IDE (version 1.0.5).  I have the ATtiny85 selected with internal 1 meg clock.   Works fine.

I re-installed Visual Micro into my VS 2012 and it works fine for non-tiny boards.  

If I open VS 2012 and check Tools>Visual Micro>Programmers I see UBStinyISP and can check it.  So far so good.

If I then start a new Arduino project - say tinyBlink3 I can build a simple blinker program that ran under the Arduino IDE.  I select Tools>Visual Micro>Programmes and again select USBtinyISP.

When I compile and run I get:

 Board Properties
name=ATtiny85 (internal 1 MHz clock)
bootloader.low_fuses=0x62
bootloader.high_fuses=0xdf
bootloader.extended_fuses=0xff
upload.maximum_size=8192
build.mcu=attiny85
build.f_cpu=1000000L
build.core=arduino:arduino
build.variant=tiny8
runtime.ide.path=C:\Program Files\arduino
build.system.path=C:\Users\James Brown\Documents\Arduino\hardware\attiny\system
runtime.ide.version=105
originalid=attiny85
vm.core.include=arduino.h
vm.boardsource.path=C:\Users\James Brown\Documents\Arduino\hardware\attiny
vm.platformname.name=avr
build.arch=AVR
ide.hint=Arduino 0023 and 1.0.x Ide
ide.location.key=Arduino
ide.location.ide.winreg=Arduino 1.0.x Application
ide.location.sketchbook.winreg=Arduino 1.0.x Sketchbook
ide.location.sketchbook.preferences=sketchbook.path
ide.location.sketchbook.default=%MYDOCUMENTS%\arduino
ide.location.preferences=%VM_APPDATA_ROAMING%\arduino\preferences.txt
ide.default.package=arduino
ide.default.platform=avr
ide.multiplatform=true
ide.includes=arduino.h
ide.platformswithoutpackage=true
ide.sketchfolder.platforms.exclude=avr
ide.includes.fallback=wprogram.h
ide.extension=ino
ide.extension.fallback=pde
ide.versionLTEQ=149
ide.exe=arduino.exe
ide.hosts=atmel
ide.url=http://arduino.cc/en/Main/Software
vm.debug=true
software=ARDUINO
ide.appid=arduino10x
location.sketchbook=C:\Users\James Brown\Documents\Arduino
compiler.path=C:\Program Files\arduino\hardware\tools\avr\bin\
includes= -I"C:\Program Files\arduino\hardware\arduino\cores\arduino"  -I"C:\Users\James Brown\Documents\Arduino\hardware\attiny\variants\tiny8"
build.path=C:\Users\James Brown\AppData\Local\VMicro\Arduino\Builds\tinyBlink3\attiny85
build.project_name=tinyBlink3
build.variant.path=C:\Users\James Brown\Documents\Arduino\hardware\attiny\variants\tiny8
archive_file=core.a
object_file=C:\Users\James Brown\AppData\Local\VMicro\Arduino\Builds\tinyBlink3\attiny85\WString.cpp.o
source_file=C:\Program Files\arduino\hardware\arduino\cores\arduino\WString.cpp
object_files="C:\Users\James Brown\AppData\Local\VMicro\Arduino\Builds\tinyBlink3\attiny85\tinyBlink3.cpp.o"
build.architecture=avr
vmresolved.compiler.path=C:\Program Files\arduino\hardware\tools\avr\bin\
vmresolved.tools.path=C:\Program Files\arduino\hardware\tools\avr

Compiling 'tinyBlink3' for 'ATtiny85 (internal 1 MHz clock)'
Build folder: tiny85
Binary sketch size: 836 bytes (used 10% of a 8192 byte maximum) (0.19 secs)
Uploading to I/O board using 'usbtinyisp'  

But it hangs there.  It never finishes the load.

Rechecking Tools>Visual Micro I verify that 'Upload Using the programmer' is checked.

Any idea?

I'm not sure what you asked me to do but I did reload the attiny folder into:
C:\Program Files\Arduino\hardware\attiny
It now has boards.txt and a directory called variants.

I did "Tools>Visual Micro>Reload Toolchain" as well.

No change.  

I can still program the ATtiny85 installed  on the USBtiny85 programmer using the Arduino 1.0.5 GUI fine.

When I open Tools>Visual Micro> the "programmers" field is grayed out.  That doesn't seem right!!

Sweet - 
Thank you for giving me back the one tool I use for all my programming tasks.
Keep up the good work.

Thanks that is a good point and reminds me to investigate something which you might know for sure.

The alternate "custom" hardware library folders used to be located off the SketchBook folder which defaulted to  documents\arduino. The SketchBook folder can be altered in the Arduino Ide File>Preferences.

Someone reported that these "custom" folders are no longer located under the SketchBook folder but now hardcoded to the "documents\Arduino" folder. 

Can you confirm the situation with this and if so then do you know in which Arduino version this change occurred? (If so will will save me hunting through the Arduino source code)

Thanks again