kalev's tefillah

the gemara in sotah 34b notices that when discussing the trip of the meraglim, the torah begins in the plural, "vayaalu banegev", but ends in the singular - "vayavo ad chevron".  the gemara famously explains: kalev by himself went to chevron to daven by the graves of his forefathers. he said: avosai - please ask g-d for mercy to prevent me from slipping into the sin of the meraglim.

is this allowed?  isnt kalev using the dead as an intermediary between himself and hashem, which is a violation of the fifth ikkar of the rambam: היסוד החמישי שהוא יתעלה הוא אשר ראוי לעבדו ולרוממו ולפרסם גדולתו ומשמעתו. ואין עושין כן למה שלמטה ממנו במציאות מן המלאכים והכוכבים והגלגלים והיסודות וכל מה שהורכב מהן, לפי שכולם מוטבעים בפעולותיהם אין להם שלטון ולא בחירה אלא רצונו יתעלה, ואין עושין אותם אמצעים להגיע בהם אליו, אלא כלפיו יתעלה יכוונו המחשבות ויניחו כל מה שזולתו. וזה היסוד החמישי הוא האזהרה על עבודה זרה, ורוב התורה באה להזהיר על זה.

so people pointed out to me the obvious distinction: maybe praying to malachim is a violation of this ikkar emunah, but praying to dead people is really just asking them to pray for you.  the same way you can ask someone who is alive, you can ask someone who is dead.

but i was a little skeptical.  so i asked rabbi google, and found http://www.globalyeshiva.com/profiles/blogs/graves-and-cemeteries-1.  the bach (YD 217) writes that it is forbidden to pray to the dead because of the issur of "doresh el hameisim."  he asks from the gemara about kalev, and says that kalev didnt daven to the dead.  rather, kalev went to kivrei avos because it was a makom of kedusah but there davened only to hashem (see the drashos haran drush 8 for a fascinating elaboration on the nature of the kedusha of kivrei tzaddikim).  but i cant understand this bach for the life of me - did he read the next line in the gemara!! (at least edit out the controversial line in his hagahos)

i just point out that this ikkar of the rambam is really a major machlokes rishonim.  this is evidenced by the practice still followed in many shuls of reciting certain selichos which ask malachim to intercede on our behalf to hashem.  for example "malachei rachamim, misharsei elyon, chalu na pinei kel bimeitav higayon..." or even more famously, machnisei rachamim hachnisu rachamaeinu lifnei baal harachamim. according to the rambam, it is a violation of no less an issur than avodah zarah to say these tefillos. other rishonim felt, however, that it is entirely appropriate to ask malachim to intercede on our behalf.  i consider this gemara about kalev a raayah to the anti-rambam camp.

 should one say these tefillos?  i dont know, and i really should ask a sheila.  my eitzah for machnisei rachamim these past few years has been to daven slowly so that i dont have time to say it - making it a non-issue (unfortunately, that usually doesnt work for malachei rachamim, which is recited responsively.)

im looking for mekoros on this issue- if anyone has, i'd love to hear them.